Free Shipping On Orders Over $49. Details

Talk to a Mustang Enthusiast
1-877-887-1105
M-F 8:30A-11P, Sat-Sun 8:30A-9P
Win $5,000 For Your Mustang! Enter daily!

SLP Catted X-Pipe (99-04 4.6L)

$0.00
Market Price $454.95 You Save 4% ($18.00)
Our Price

$436.95

FREE Shipping

  • Item 23008

Will this fit your Vehicle?

In Stock Ships same business day.
Ship to: Ashburn - 20149
Sorry, please enter a valid US or CA postal code
We're sorry, zip can't be updated at this time.
    Create a list
    Add to New List

    Saved - View your saved items

    We're sorry. We couldn't save this product at this time.

    Features & Details

    • Increases Horsepower and Torque
    • Race Car Growl
    • Three-Piece "Modular" Design
    • High-Flow Catalytic Converters
    • 2.5" Mandrel-Bent Stainless Steel Tubing
    • Fits 99-04 GT, Bullitt, Mach 1, and Cobra
    More Power and Torque. The SLP X-Pipe uses free-flowing mandrel-bent tubing with a genuine X style crossover and high-flow catalytic converters to provide a significant increase in horsepower and torque over the restrictive stock catted pipes.

    Race Car Growl. This free flowing SLP x-pipe for the 1999 to 2004 Mustang's not only increases power, but it also adds a raspy, race car growl to the sound of your exhaust with its modern "X" crossover pipe design.

    Upgradable Modular Design. SLP's exclusive three-piece modular design makes it possible to easily upgrade to SLP's Long-Tube Headers without the need of purchasing a brand new X-Pipe by just removing the down pipes. This unique modular design also makes it easy to install this X-Pipe on your Mustang with just basic hand tools.

    Quality Stainless Steel Construction. Constructed entirely from 2.5" mandrel bent stainless steel tubing for improved exhaust flow, this SLP Mid Pipe features a true "X" crossover, not a poor-flowing clam shell imitation that other companies use. The included SLP High flow cats far out perform the restrictive stock catalytic converters to increase rear wheel horsepower and torque.

    Application. This Catted X-Pipe from SLP is designed to be a direct bolt-on for the 1999-2004 GT, 2001 Bullitt, 2003-2004 Mach 1, and 1999-2004 SVT Cobra Mustangs with either aftermarket short tube headers or the stock manifolds and a dual catback exhaust installed.

    Technical note: 2004 SOHC and DOHC applications require the use of 18" O2 sensor plug-in extender wires.

    Fitment: 1999 2000 2001 2002 2003 2004 Details

    MPN# M31032

    CA Residents: WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov

    What's in the Box
    Hardware included:
    • (4) 2.5" band clamps
    • All required fastners (nuts, bolts, washers)
    • Flange gasket
    Installation Info
    Tech Specs
    Mid Pipe Specifications
    Style Mid Pipe: Standard/Shorty length "X" Type Headers Required: Shorty/Long Tube
    Piping Material: Stainless Steel Piping Size: 2.5"
    Catalytic Converter: "Yes" Fitment: 1999-2004 GT, Bullitt, Mach 1, and Cobra Mustangs.
    Will it fit my Mustang?

      Customer Photos (22) Submit Your Photo

      View All 22 Photos

        Questions & Answers (14)

        5 Top Rated Questions

        Is this CA Emissions legal?

        • This is a tough one. The catted x pipe should pass the sniffer test during emissions, the bigger issue is the visual inspection. You would need to find a place that only does the sniffer test. Might be easier to just move to another state.

        Helpful (5) Show 1 more answer

        Is it necessary to have long tube headers with this for an 01 gt?

        • Unfortunately this x-pipe will not work with long tubes. You would need shorty headers or the stock manifolds.

        Helpful (0)

        Is this legal in New York Long Island?

        • The x-pipe uses high flow catalytic converters which may not be legal in some states. Especially for states that have adopted California's emission laws. We highly recommend reaching out to a local shop or state ordinances to confirm if the part will be legal in your state.

        Helpful (0)

        Do the cats just bolt on? If so, can you replace them with just piping?

        • The SLP Catted X-Pipe uses band clamps to attach the catalytic converters. If the cats were to be removed, they would need to be replace with an exhaust portion of the same dimensions.

        Helpful (0)

        Are the downpipes compatible with BBK 1-5/8 in. Chrome Shorty Headers for a v6 mustang?

        • This Catted X-Pipe from SLP is designed to be a direct bolt-on for the 1999-2004 GT only and will not work with the V6 models due to different piping size.

        Helpful (0)
        Post Your Question
        9 More Questions
        Will this fit a 2003 Cobra? Will this also bolt onto some borla stingers? 1 answer
        I plan on installing a duel exhaust on my 04 v6 mustang and was wondering if these will work with the stock headers my car already has. Choice of exhaust is slp loudmouth. 1 answer
        Is this catted x pipe carb certified? because i live in CA and if its not then are there any catted x pipes that are certified? 1 answer
        I have this x-pipe installed on my 03 GT already. Will SLP long tube headers work with this x-pipe? I assume the extra tubes right after the cats can be removed and you can hook up the LTH? 1 answer
        I just have SLP LM1 catback on my 03 GT right now, but switching from stock H to this SLP catted X-pipe what HP gains will I see? 2 answers
        Does this slp x-pipe fit the 4r70w automatic cars 1 answer
        Engine light and 02 sensors If I install this on my 2003 mach 1 will the high flowing cats cause my check engine light to come on and should my 02 sensors reach or will I need extensions? 1 answer
        WILL IT WORK WITH MAC LONG TUBE TF9902 1 answer
        X-Pipe with SLP Long Tube Headers and Glass Pack Tips? I already have glasspack tips on my mustang, but if I were to install the SLP longtube headers with the SLP Catted X-Pipe, could the glasspack tips still be reused? 1 answer

          Customer Reviews (98) Write a Review

          Overall Rating 4.5

          out of 5 stars

          Installation Time:Afternoon

          Installation Cost:$100-$250

          • Loudness / Volume 4.333333 4.3
          • Exhaust Note 4.520833 4.5
          • Fit & Finish 3.979167 4.0
          • Bang For Your Buck 4.0625 4.1



          • 5/5

            Installation Time: Less than 1 Hour

            June 05, 2019

            Alp cated x pipe

            Great product fits great sounds amazing would recomend to anyone

            Charlest

            Year: 2004 Submodel: GT

            Helpful (0)

          • 2/5

            Installation Time: Full Day

            May 05, 2019

            Disappointed

            Got this xpipe kit last March, and have owned it for about over a year. Pro's: sounds pretty good Cons: terrible fitment, Leaks like crazy no matter how much you adjust it, it hangs stupid low to the ground, was a pain to hook up to the headers, oh and the cats that come on it will not let you pass emmisions. So now I gotta spend a few hundred freedom bucks to get bigger cats welded to the system. Thanks SLP for putting cats on the system even though it'll cause you not to pass inspection.

            MBlaze

            Year: 2002 Submodel: GT

            Helpful (1)

          • 2/5

            Installation Time: Full Day

            November 01, 2018

            Great sound, awful fit

            The sound is awesome. I have it paired with the loudmouth and it just sounds like pure race car. BUT the fitment is awful. The cats sit super low. The pipe coming off the headers could have an inch or two shaved off and it would fit much better. Also the fitment to the header manifold on the driver side is horrendous. I will probably be changing this out for the Bassani X-pipe very soon.

            Josh

            Year: 2000 Submodel: GT

            Helpful (4)

          • 5/5

            Installation Time: Afternoon

            June 21, 2018

            2003 Mustang GT

            Yes the right side cat hangs quite low, but it has given my car a perfect sounding exhaust!

            AndrewO

            Year: 2003 Submodel: GT

            Helpful (5)

          • 3/5

            Installation Time: Full Day

            May 21, 2018

            Stang gt

            Even though you guys sent me the wrong catalytic converter(s), you did make up for it and overnight me the correct ones. Once they installed the entire exhaust system, I was very pleased with the sound of the x-pipe with the borla s-type exhaust.

            terry1

            Year: 2000 Submodel: GT

            Helpful (5)

          • 5/5

            Installation Time: Full Day

            April 19, 2018

            X pipe

            Awesome kit little bit of a pain to do the passenger side manifold studs but after some words with the car lots of free all and bunch of sockets and swivels it’s on sounds great

            TimF

            Year: 2003 Submodel: Mach 1

            Helpful (5)

          • 5/5

            Installation Time: Afternoon

            April 04, 2018

            SLP catted X-Pipe

            Great X pipe! Easy install just takes time to adjust the Length of exhaust to fit perfectly. Awesome sound and quality welds and clamps.

            ChrisK

            Year: 2003 Submodel: Cobra

            Helpful (5)

          • 3/5

            Installation Time: Shop Install

            Installation Cost: $250-$500

            August 15, 2017

            Raspy sound

            I bought this SLP catted X pipe for improving airflow from my SLP loudmouth exhaust and that made a huge difference in power at high RPM's. But this X pipe change my cat-back exhaust note to a very very raspy sound. That's terrible combined with the SLP loudmouth 1. Maybe SLP loudmouth 2 or long tube headers can improve the sound. The stock H pipe was a nightmare to take off at the shop. All the studs broke from the left manifold. Those broken studs cost $$$ to remove. Luckily this SLP X pipe fit very well and the overall quality are exellent. No check engine light. Thanks AM.

            Fastang

            Year: 2003 Submodel: GT

            Helpful (13)

          • 5/5

            Installation Time: Less than 1 Hour

            June 25, 2017

            Very happy with it

            It took me a while to decide which mid pipe to get and I'm glad I went with this one. I didn't want a bbk one because it seems everyone has that one so I wanted to try something different and I like it. It gives the car a much better sound and it's actually pretty loud even tho it's got catts on it. My only problem is that it sits very low.

            carlosf12

            Year: 2004 Submodel: GT

            Helpful (5)

          • 5/5

            Installation Time: Afternoon

            June 09, 2017

            Great Product

            Great Product for a great price, would recommend getting a tune and adjusting your idle. Since I installed these my car has been running rich and stalling out. I fixed the stalling by adjusting the idle but will buy a tuner soon for the problem of it running rich. Also the cats sit very low so keep in mind you will need to baby your car over speed bumps or you will scrape them.

            Jbr95

            Year: 1999 Submodel: GT

            Helpful (6)

          • 5/5

            Installation Time: Afternoon

            May 29, 2017

            Beautiful!

            Installation was a piece of cake, other than the driver side studs on the exhaust manifold of course lol those were tough but with proper tools it can be easy. It sounds great and paired with my 40s, it really comes to life with a very moderate raspy sound. Not obnoxiously loud, but definitely a head turner. On My down side is how low the cats hang. I have stock height on my car and it still makes me nervous.

            GabeC

            Year: 2002 Submodel: GT

            Helpful (4)

          • 3/5

            Installation Time: Full Day

            April 25, 2017

            Do your Cats hang low do they wobble to the floor

            I had some MAJOR issues with fitment of this system. I was replacing the Pypes O/R X Pipe after close to a decade of solid performance. I finally decided not to have a car that can be heard from miles away so I opted to put on a catted X Pipe. I have an SLP LM1 Cat-Back that has been on for over a decade and I couldn't be happier with it. Still looks and sounds great. My issue with the SLP X Pipe was when it was all installed (which was a pain in the rear). Drivers side removing the studs was an issue (had to use a bolt extractor that I hammered on), and the passengers side was a nightmare to get access to the bolts even with wobbles, u-joints, and extensions. However, I did eventually get it all together, and put a jack under it to fit it as tightly against the under carriage that I could get it. Sadly the cats were extremely low. I had about 3 inches of clearance. I decided to drive it to the local exhaust shop to have them see if they could improve the fit. He had to cut the pipes that connected to the exhaust manifold, and re-weld them to tuck them up out of the way. Luckily they do great work for practically peanuts so I was only out about 50 or so bucks and they fit reasonably well now, but they should out of the box fit beautifully, especially since it was connecting to another SLP product. I rounded up this review to 3 stars, (really it's 2.5) but I think SLP as a brand has nice quality and it lasts a long time so thus the bump. So be aware, you might have to really fight to get this thing fitting well, especially those with lowered cars.

            SonictheGT

            Year: 2004 Submodel: GT

            Helpful (4)

          • 4/5

            Installation Time: Less than 1 Hour

            April 18, 2017

            Sounds awesome, exhaust leak.

            I was excited to receive my x pipe, the pipes looked fine and I love the three piece design is really easy to work with, complaint it hangs very low and it has a leak, I am not happy with it and I wish I paid 100$ more for the bassani. Exhaust note is on point though .

            svtdavvy

            Year: 2001 Submodel: Cobra

            Helpful (5)

          • 3/5

            Installation Time: Afternoon

            March 20, 2017

            Great sound poor fit

            Had this on my mach 1 with 18" wheels and stock ride height yet this x pipe would scrape on speed bumps. I had this paired with my Borla Atak and the combo was great, everything I expected however the car was more or less undriveable in everyday life since speed bumps were any issue. If speed bumps are not an issue for you I say get this X Pipe the sound is unreal.

            TimJ

            Year: 2004 Submodel: Mach 1

            Helpful (5)

          • 4/5

            Installation Time: Afternoon

            February 03, 2017

            Great sound.

            I love the sound of the x pipe. Especially when you step on it! Has a great raspy sound and is loud but next to loud. The only thing is that it does hang a little to low. I don't think I would approve if my stang was lowered.

            BenW

            Year: 2002 Submodel: GT

            Helpful (4)

          • 5/5

            Installation Time: Shop Install

            Installation Cost: $100-$250

            December 21, 2016

            SLP loudmouth kit

            I love the sound. Loud and deep! I had a shop install cause I didn't have time but it sounds amazing and if you don't like to hear yourself think then this is the way to go

            MRoberts1227

            Year: 2003 Submodel: GT

            Helpful (5)

          • 5/5

            Installation Time: Shop Install

            Installation Cost: $100-$250

            December 12, 2016

            99-04 Mustang GT SLP High Flow Catted X pipe

            This X pipe is awesome! I had it installed by a shop and it took about an hour and a half. The tone is so much more aggressive than stock. It is louder than stock but not by to much. I have had off road x pipes in the past and this has a very similar tone to an off road pipe but is not as loud and is less raspy. It is so deep and aggressive sounding when paired with my Flowmaster Exhaust. The car does seem to have better throttle response now however do not expect this to be a large performance increase without a tune, but it is well worth the money for the sound it provides.

            MaxPower

            Year: 2001 Submodel: GT

            Helpful (4)

          • 5/5

            Installation Time: Afternoon

            November 21, 2016

            Awesome!

            Great fitment with my SLP LM1 catback. Went from the Bassani O/R X to this one, while the Bassani sounded great it was just too loud to do anything with. The SLP took the edge off, it's still loud and I think it sounds even better. Great product!

            Killanik

            Year: 2002 Submodel: GT

            Helpful (6)

          • 5/5

            Installation Time: Less than 1 Hour

            May 17, 2016

            awsome

            The items is awsome. I didn't have any trouble putting the new one on. It was like a 30 min job. They sound awsome and glad I went with this product. I will be doing this to my other car soon. Overall I'm very happy with the results.

            b

            Year: 2003 Submodel: Mach 1

            Helpful (5)

          • 5/5

            Installation Time: Shop Install

            Installation Cost: $100-$250

            April 02, 2016

            Totally Awesome!

            I thought my 04 Mach 1 (auto) was good enough with an SLP Loudmouth 1 cat back exhaust installed, but when I married this up to the SLP Catted X-Pipe, a CandL CAI and had it professionally tuned, was when I realized I should have done this long ago! The modular design of the SLP X-Pipe and Cat Back system made installation rather easy and the raspy sound is not for the feint of heart. Once the Catted X-Pipe was installed and the tune set up was when my old pony woke up and realized it may not be the newest or quickest kid on the block, but now it can keep up and run 'em down.

            mjksvt

            Year: 2004 Submodel: Mach 1

            Helpful (4)

          Related Mustang Categories