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Pypes Catted X-pipe (99-04 GT)

Market Price $443.99 You Save 12% ($52.00)
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  • Item 20039
  • MPN# XFM36

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Features & Details

  • Balance Out Exhaust Gases for More Power
  • Raspy Race Car Growl
  • Pypes Modular Construction
  • High-Flow Catalytic Converters Included
  • 2.5" 409 Stainless Steel Tubing
  • Fits 1999-2004 GT Mustangs
Balances Exhaust Gases. The Pypes Catted X-Pipe is excellent when it comes to balancing out the gas pressures in your exhaust system. This Pypes x-pipe creates more power and torque than a traditional H-pipe. Why? Because the exiting exhaust pulses are merged at the "X", resulting in less exhaust back pressure for more power.

Race Car Growl. This free flowing Pypes x-pipe for the 1999 to 2004 GT'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.

Modular Construction. Pypes unique three piece modular construction makes it quick and easy to add or remove catalytic converters to your exhaust system in just minutes, depending on your driving needs.

Durable Stainless Steel Construction. Pypes uses sturdy 16 gauge 409 stainless steel mandrel bent 2.5" tubing for improved exhaust flow and features welded reinforcement plates for additional strength. The included High flow catalytic converters far out perform the restrictive factory cats to provide a significant increase in horsepower and torque.

Application. This Pypes Catted X-pipe is designed as a direct bolt-on for the 1999 to 2004 4.6L GT Mustangs with either aftermarket short tube headers or the factory manifolds and a dual catback exhaust installed.

Technical note: 2004 Mustangs require the use of 24" O2 sensor plug-in extender wires.

Fitment: 1999 2000 2001 2002 2003 2004 Details

What's in the Box
Hardware included:
  • (4) 2.5" band clamps
  • All required fastners (nuts, bolts, washers)
Installation Info
Tech Specs
Mid Pipe Specifications
Style Mid Pipe: Standard length "X" Type Headers Required: Shorty
Piping Material: 409 Stainless Steel Piping Size: 2.5"
Catalytic Converter: "Yes" Fitment: 1999-2004 GT Mustangs
Will it fit my Mustang?
  • GT - 99, 00, 01, 02, 03, 04

Fits GT only

Most Helpful Reviews


Sound=10 Quality of material=8 Fitment = 6 I recenlt purchased the pypes kit and i give it 3 stars because of the fitment . The cutting of the pypes was cake but when the install came nothing was close ...

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Helpful (8)

not 100%

Was unhappy when i went to line everything up. did not go together very well, everything was off. i have a tiny exhaust leak now because of it. but i guess you get what you pay for if you want a better ...

Read More
Helpful (4)

Overall Rating 4.1 out of 5 stars
Read All 16 Reviews

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6 Questions / 6 Answers

Ask a Question

Would this fit in a 2000 v6?


  • This will not fit a 2000 V6 Mustang that has not been converted to the dual exhaust.


Helpful (0)

So i will be able to run it with out the cats on it and the pipe will still fit. I wouldn't have to put pipe in where the cat should be?


  • Hey Adm, Pypes actually has a pipe if you don't want to run catts that bolts directly up to the factory manifolds item# 20004


Helpful (0)

Can I put the x pipe on with out the cats. But when I do emissions can I put them back on? And my pipes are 2 1/4, will this 2.5 in pipe work with 2.25in pipe?


  • Since these catalytic converters are clamp ons, you will be able to delete the cats for emissions checks. Also, this mid pipe will work with a 2.25" pipe.


Helpful (0)

Fit on stock Catback Will this bolt onto my stock catback? I know its 2 1/4 piping but I don't know if it will bolt on properly or be restricted cause of the smaller piping. I only changed the muffler on the car and the rest is stock. Do we also need a tune for this X-Pipe or can we just bolt it on?


  • Yes


Helpful (0)

Will this work for my exhaust? Will this work for a Cherry Bomb Extreme Dual Exhaust?


  • That will be a custom setup, you will have to modify the Pypes Catted X-pipe (99-04 GT) to work with Cherry Bomb Extreme Exhaust.


Helpful (0)

Is my exhaust compatible/easy to connect? I purchased the Pypes violator catback exhaust system for my car and had the mechanic install them for me. I wanted to know if these X pipes are going to be fine for the exhaust system. Now that i see that both have 2.5 inch tubing, there shouldn't be a problem, and i didn't change my headers, so they should technically fit, right?


  • If you have a 99-04 GT, this X-pipe will be a direct replacement for your stock mid-pipe! You won't have any problems installing with your stock headers or Violator catback!


Helpful (0)

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Customer Reviews (16) Write a Review

Overall Rating 4.1

out of 5 stars

Installation Time:Full Day

Installation Cost:$100-$250

  • Loudness / Volume 5 5
  • Exhaust Note 5 5
  • Fit & Finish 4 4
  • Bang For Your Buck 4.75 4.8

  • 3/5

    April 25, 2010


    Sound=10 Quality of material=8 Fitment = 6 I recenlt purchased the pypes kit and i give it 3 stars because of the fitment . The cutting of the pypes was cake but when the install came nothing was close to lining up. I used a car lift which was very helpfull. The fitment was off by inches every which way. For a tip, a good ratchet strap can help pull things in place.(thats what i had to use). But other than fitment it was great but my opinion if you have the little extra money i would go with a little better brand.


    Helpful (8)

  • 3/5

    September 27, 2010

    not 100%

    Was unhappy when i went to line everything up. did not go together very well, everything was off. i have a tiny exhaust leak now because of it. but i guess you get what you pay for if you want a better pipe then pay the extra cash.


    Helpful (4)

  • 1/5

    April 09, 2010

    Worest Fit EVER

    I'm attempting to install the Catted X-Pipe in my 2000 GT. This is the worest fitting X-Pipe I have ever seen. The x-pipe to cat flange on the passenger's side is about 2-3" off (pointed towards the front tire). I've wrestled with this for over 4 hours. I finally got the down pipe, cats, and x-pipe connected (barely!). Now the line-up with the Cat-bac exhaust is off. I don't see how this is going to "seal". I'm guessing I'll have exhaust leaks all over the place. I've TRIED to contact Pypes tech-support, complete waste of time. I am totally dissatisfied with this product and their customer service. I will never purchase PYPES again. American Muscle has been great, they've been as helpful as they can be. The problem is not them, it is Pypes.


    Year: 2000 Submodel: GT

    Helpful (4)

  • 4/5

    July 25, 2016

    Happy Cat

    The product came in on time an installed without a hitch. Very happy with product.


    Year: 2003 Submodel: GT

    Helpful (2)

  • 5/5

    May 02, 2010

    Vicious Exhaust

    I bought this x-pipe a few weeks ago and eventually gave in and bought Pypes' high-flow cats before getting it installed. Right after the install, I was a bit disappointed with the sound. However, as the days have passed, my exhaust has become gradually louder and louder and the tone has drastically changed. I have this paired with a Magnaflow Magnapacks catback (which sounded great on its own) and together they sound fantastic. Even with the cats, the x-pipe sounds vicious and made a huge difference. I had mine professionally installed and it did not take more than three hours. Recommended!

    Steve Bolger

    Helpful (2)

  • 5/5

    October 19, 2008


    Sounds awesome! Only thing negative I have to say about this, is that its not made to fit right out of the box. Cutting was required to fit the cats on, and I was not prepared right away. Sounds awesome though.


    Helpful (2)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $100-$250

    April 28, 2014

    Love the sound and increased performance....

    I was apprehensive about doing this myself. After much deliberation I decided to have the local muffler shop do it for me. I was in the shop roughly 2.5 hours. The actual amount of time they worked on it was 1.5 hours. I'm glad I had them do it, as it had the original exhaust and 107,000 miles on it and I would have had to cut the bolts that connected both ends. Even though it is a 2004 and the instruction said I didn't need the O2 extensions, neither side would reach the back of the cats. After releasing the harness, the passenger side was able to connect. I had to order the extensions to get the drivers side connected. It still has the original Ford mufflers and sounds great!


    Year: 2004 Submodel: GT Oxford Charter Township, MI, USA

    Helpful (1)

  • 5/5

    Installation Time: Afternoon

    August 11, 2012

    Decent fitting pipe at a great price.

    Fit pretty good on my mustang and doesn't hang excessively low. The cats have their own O2 holes/bungs so it's easy to add a wideband sensor if you'd like.


    Year: 1999 Submodel: GT Central PA

    Helpful (1)

  • 5/5

    April 26, 2010

    Pypes X-pipe Catted

    I installed this on my 2002 GT, i had already installed slp loudmouths before installing this, i removed the old pipes and converters, unplugged O2 sensors ect... to help everyone out while installing this: the original downpipe will need to be cut 9.5" to incoprate the cats, after this i started by bolting the driverside down pipe, a gasket is not required stock but for a fitment issue i had i bought a donut gasket bacause the pipe didnt fit snug, while bolting the passanger side you may still have the flanged gasket or have to buy a new one, i then clamped the new cats on and then added the X-pipe portion, it was a snug fit but you will get it, i added new studs to the endpipe midpipe flange part to secure it together. the sound from this pipe is great and clean, its wonderfull and i recomend it tho the difficulty of the install, i also did this with my car on jack stands so everyone can do it. Go American Muscle!!!!!!!!


    Year: 2002 Submodel: GT

    Helpful (1)

  • 4/5

    March 07, 2010

    Pypes x pipe

    This product was very easy to install. I was a little scared on having to cut the pipe to fit the cats but ended up doing good. I loved the price and the HP gain wasnt that bad and also great sound.

    Mr. Pelonee

    Helpful (1)

  • 4/5

    May 22, 2009

    Awesome x pipe

    They sound great. Install is not so much fun. Watch those passenger side header bolts! Quiet idle. I wish it was a little louder. but it sounds great when opened up. I have a slight love hate with the high flow cats. Keeps me legal but still a little quiet for my taste. Noticed a power increase too.


    Helpful (1)

  • 5/5

    November 24, 2008

    Pypes catted x pipe

    I am very content with my purchase of this pipe. It isnt as loud as the off-road pipe I used to have, but the cats that come on it dont seem too restrictive compared to stock. It sounds fine and is a good combo with my shorty headers. It passed Indiana emissions with flying colors with these on. Although, I dont know if they hooked me up or not.


    Helpful (1)

  • 5/5

    October 14, 2008

    Sick X Pipe

    I purchased this x pipe and it sounds great. I am running no cats right now, lol (not exactly legal), but even with the cats in Cali its not street legal. Oh well, it sounds awesome and adds good power.


    Helpful (1)

  • 3/5

    June 29, 2017

    Great sound, bad fit.

    Got them installed and the o2 bung didnt even have complete threads in one of the cats,, had to weld a bung on a bung just to keep my o2 sensor in there.


    Year: 2004 Submodel: GT

    Helpful (0)

  • 5/5

    Installation Time: Afternoon

    May 26, 2017

    aggressive sound

    this x pipe will definitely give u better air flow and aggressive sound coupled with flow master mufflers...sounds good i had a bad factory cat which kept blowing off my back pressure hose ..remedied


    Year: 1999 Submodel: GT

    Helpful (0)

  • 4/5

    August 21, 2009

    Pypes 409 Stainless Steel Catted X-pipe (99-04 GT)

    very nice sound and excellent quality

    Dale B

    Helpful (0)

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