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

Item 23008
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      Video Review & Installation

      Man 1: The SLP Catted X-Pipe that we have here today will be a great option for the '99 to '04 V8 powered new edge owners who are looking to replace their factory mid-pipe with something that will increase both the sound and the performance yet still maintain a set of high flow cats, as opposed to going to something off-road. Now, notables of the SLP here do include that full stainless steel build along with the two-and-a-half-inch diameter off of the mid to high $400 price point. Install this piece here, we'll get a solid two out of three wrenches according to the site and take a couple of hours at least to complete from start to finish. But if you hang with me for a bit, guys, we'll walk you through that job later in the video, let's just jump right into the SLP here guys. And since most owners are probably installing this more for sound purposes, let's briefly break down the sound clips you heard at the very top of this video.And listen, since you are switching your factory, mid-pipe from an H to an X along with adding some high flow cats into the equation, you're really gonna be changing up the entire tone of the exhaust overall. Now, that's not to say you're adding a bunch of volume here, but you're certainly adding a little bit more rasp. So going to my wake to neighbor scale, I have the SLP mid-pipe coming at a strong two out of five, out my one to five or again, one to awake to neighbor scale with the stock exhaust in place. Now switch that out for a more aggressive system and I would certainly expect a good bit more volume here with the SLP in place. And that's something our customers have pointed out in the review section. So as always guys feel free to read up on those from owners who have installed this with some different exhaust systems and have really commented on their experience. But with the sound covered, what do you say we talk about quality and construction. And listen, if you guys know the SLP brand, you know you're certainly gonna be getting a good bit of both, right? Quality and construction. Now, starting with materials here, guys, owners can look forward to a full stainless steel build 409 grade to be exact, which will be very clutch in reducing corrosion over the years.Now, this option does again, incorporate a pair of high flow cats along with a two and a half inch mandrel bent tubing and the mid-pipe itself we'll include both the flanges on both ends here to work with either your factory or aftermarket cap back of your choosing along with, again, your factory manifolds or even a set of aftermarket shorty headers. But as this mid-pipe sits right now, this is essentially a full-length mid-pipe, so therefore it will not work with a set of long two headers. However, since the SLP design is modular one, owners can add SLP's long two headers down the road, which will basically eliminate these two pieces of pipe, and at that point, everything will work just fine. And that is a nice thing to point out here, something that this mid-pipe will allow. But now we wanna switch gears guys and give you a better idea of just what it takes to get this mid-pipe installed on your new edge at home. So, without further ado check out our detailed walkthrough and tool breakdown right now.Man 2: Tools for this install, an impact a 15-millimeter deep socket, as well as 15-millimeter swivel socket, a 14-millimeter socket, 14-millimeter wrench, a seven-eighth wrench, and an extension. Hey guys, for this uninstall, we're gonna start by uninstalling our O2 sensors, that way we don't get snagged up when we're moving our pipes. We're gonna first undo them from the pipes as well as unplug them from their actual sensor. First, start by unplugging your sensors from their harness. And then we can grab our seven-eighth wrench and start undoing them right above the H-pipe. Now, we will be reusing these, so just set them off to the side. Now, for the front sensors, we're gonna unplug them from the harness up top, and then we'll take our sensors out of our pipes as we have them off the car. Now, grab your 15-millimeter swivel socket and extension. So we could undo the bolts at the flange. Once you have those removed, we're gonna move on to the H section. And repeat that on the other side.Now, using our 14-millimeter socket undo the flange after the H. And that's gonna be on both sides. And remove your stock H-pipe. Now, with your cats fully removed, that gives you access to your O2 sensors. So once again, grab your seven-eight wrench and get these sensors out of the pipes. Set these aside again, because we will be reusing them. Now that we have our sensors out, we could transfer them over to our new exhaust. And using our same seven-eighth wrench, tighten up your sensor. Now, taking your new downpipes, place that onto your flange. And using your stock hardware, hand tighten for now. That way, we can come back and adjust when we need to. And plug in your O2 sensor. And repeat that on the passenger side.Now, taking your kit-provided clamps, grab one of them and one of your cats and place them onto your downpipes. Now, before we put our X-Pipe onto our cats, go ahead and replace the sensors back in the orientation that we removed them. And with that same seven-eighth wrench, give them a couple of turns. Now, take your X-Pipe and a couple of clamps and place them onto your cats and start lining them up with the flange at the back end as well. And with the kit-provided hardware, connect your flange and your new X-pipe. Hand tighten for now, and then we'll come back and re-tighten with our tools in a moment. Now, plug in your sensors. Now, with a 14-millimeter wrench and a 14-millimeter socket, tighten down your flange bolts. For your clamps, it's going to be a 15-millimeter socket. You can go ahead and tighten them down now as well. Now, we can bolt down our flange using our 15-millimeter swivel socket. And finally, repeat that on the other side. And that's gonna wrap it up for our review and install of the SLP Catted X-Pipe fitting your '99 to 2004 GT. For more videos just like this, keep it right here at

      Product Information

      Features, Description, Reviews, Q&A, Specs & Installation

      Features & Specs

      • 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.



      SLP M31032

      CA Residents: WARNING: Cancer and Reproductive Harm -

      Installation & What's in the Box

      Installation Info

      What's in the Box

      Hardware included:
      • (4) 2.5" band clamps
      • All required fastners (nuts, bolts, washers)
      • Flange gasket


      Customer Reviews (173)

        Questions & Answers

        10 More Questions

        Will It Fit My Mustang

        • Bullitt - 01
        • Cobra - 99, 01, 03, 04
        • GT - 99, 00, 01, 02, 03, 04
        • Mach 1 - 03, 04

        Fits GT, Mach 1, Bullitt, and Cobra

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