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

Market Price $454.95 You Save 4% ($18.00)
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$436.95

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  • Item 23008
  • MPN# M31032

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    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

    CA Residents: Warning: California's Proposition 65

    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?

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    Questions & Answers (13)

    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 (3) Show 1 more answer

    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)

    Will this fit a 2003 Cobra? Will this also bolt onto some borla stingers?

    • The SLP Catted X-Pipe is designed to fit all V8 Mustangs from 1999-2004, including the 2003 Cobra.

    Helpful (0)
    Post Your Question
    8 More Questions
    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

    People Who Bought This Item Also Bought

    Customer Reviews (96) Write a Review

    Overall Rating 4.5

    out of 5 stars

    Installation Time:Full Day

    Installation Cost:$100-$250

    • Loudness / Volume 4.347826 4.3
    • Exhaust Note 4.521739 4.5
    • Fit & Finish 4.021739 4.0
    • Bang For Your Buck 4.108696 4.1



    • 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 (1)

    • 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 (3)

    • 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 (4)

    • 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 (4)

    • 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 (4)

    • 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 (11)

    • 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 (4)

    • 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 (4)

    • 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 (3)

    • 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 (4)

    • 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 (3)

    • 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 (3)

    • 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 (3)

    • 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 (3)

    • 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 (3)

    • 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 (3)

    • 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 (3)

    • 5/5

      Installation Time: Shop Install

      Installation Cost: $250-$500

      March 11, 2016

      Solid product

      I had to replace old X on Mustang Bullittt. This is an affordable alternative. I thought about installing myself, but ended up paying a muffler shop for install. Cost was $300 and took 1.5 hours. They said fit was nice. It's been a week and no issues. I'm happy with it.

      Hogfan

      Year: 2001 Submodel: Bullitt

      Helpful (3)

    • 5/5

      Installation Time: Afternoon

      May 14, 2015

      SCT Catted X-Pipe

      I already went the 'cat-back' route with a set of Flowmaster Super 40 Series Mufflers a few years back. Recently, I wanted to punch up the sound level a bit more, so I decided to go with an X-Pipe. I went with the SLP kit because of the positive reviews and the fact that I installed an SLP cat back system on my father in laws mach 1, and really liked the way it went together. I did try to do this in my driveway on ramps, but had no luck removing two of the four bolts. I ended up going to my local performance muffler shop and it was installed in less than one-hour. This did set me back another $150, but was worth it in the end. The new system does not have any exhaust leaks, and doesn't seem to hang too low. I have a stock height 03 mach 1 and have had no issues so far. Also, no check engine light either. The sound is great. It has a much deeper rumble or growl than before. Sounds nice leisurely going through the gears, but is the loudest under full throttle. I have no issues with any type of 'annoying' interior sounds, or 'drone' at any RPM. I think it sounds great.

      Scot3514

      Year: 2003 Submodel: Mach 1 Saint Petersburg, FL

      Helpful (3)

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