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Magnaflow Competition Series Cat-Back Exhaust (99-04 GT, Mach 1)

Item 48013
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      Review & Installation Video

      Hi I’m Justin with, and I’m taking a closer look at the Magnaflow Magnapack catback exhaust fitting the 99-04 Mustang GT and Mach 1. The Magnapack gets its name from these two Bullitt style mufflers, which are a throwback to the classic 60’s and 70’s fastback mufflers, and the sound you get from using this exhaust reflects that. The entire system features full stainless steel construction throughout including these straight through design Magnapack mufflers, the 2.5” mandrel bent tubing, all exiting out these 3.5” brightly polished tips. Because Ford chose to weld the factory exhaust on these cars, you will need to cut it off before getting started with the install. Once you have it out of the way, getting the new Magnaflow system installed should only take you about 2 hours from start to finish. Now let’s hear how Magnaflow’s Magnapack sounds compared to our factory exhaust.

      Product Information

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


      • Aggressive Muscle Car Sound
      • Competition Series Mufflers
      • 2.5" Mandrel-Bent Stainless Tubing
      • 3.5" Polished Stainless Tips
      • Fits 1999-2004 GT, Bullitt and Mach 1 Mustangs


      Free Flowing Exhaust. Magnaflow delivers the ultimate free flowing exhaust for the 1999-2004 GT, Bullitt and Mach 1 Mustangs with the Competition Cat-Back Exhaust System. By eliminating power robbing restrictions. this catback will put more horsepower and torque where it belongs - at the rear wheels.

      Aggressive Muscle Car Sound. The Magnaflow Competition Cat-Back Exhaust System, with its pair of straight-through bullet-style competition mufflers, will give your Mustang the loud aggressive exhaust note of the muscle cars of yesteryear.

      Quality Construction. Each piece is made from mandrel bent 2.5" stainless steel tubing for long life and a perfect fit. The system ends with brightly polished 3.5" stainless tips, that exit in the stock location for impressive good looks. The OEM-style barbed hangers are designed to ensure easy installation and precise fit.

      Application. Made to be a direct bolt on, this Magnaflow Competition Cat-Back Exhaust System will bolt straight up to the factory Mid Pipe without any extra modifications required on 1999-2004 GT, 2001 Bullitt and 2003-2004 Mach 1 Mustangs, to give it a deeper, aggressive sound.

      Note. Coupon codes cannot be applied to this product.

      Fitment: 1999 2000 2001 2002 2003 2004 Details

      MPN# 15673

      CA Residents: WARNING: Cancer and Reproductive Harm -


      Customer Reviews (100+)

      Write a Review

      Ratings Summary

      4.8 out of 5 overall rating from 100+ customers

      Installation Time: Afternoon

      Installation Cost: $100-$250

      • September 02, 2019

        2 2004 GT - JeffC Installation Time: Afternoon

        Magnaflow competition cat back

        Love the sound, hate the quality, passenger side great fit, driver side Up and over axle little clearance slight bumps and pipes hit sway bar. Twice now I’ve had to adjust and tightened the band clamps for the price you pay that shouldn’t be

        Helpful (0)
      • December 10, 2018

        5 1999 GT - GT35 Installation Time: Afternoon

        Just woke up my 1999

        Tight tolerances, awesome performance and sound increase

        Helpful (4)
      • November 23, 2018

        5 1999 GT - HunterP

        I have this in Cali

        To start off, I absolutely love this setup. Its loud enough to set off car alarms but not too loud as to wear your constantly waking up your neighbors if you start your car up lmao. I live in San Diego and have this set up attached to the stock 6 cats on my 99 GT and it will pass emissions tests with flying colors. So if your in Cali and want an AWESOME sound for your GT and want to stay legal, then this is the way to go.

        Helpful (6)
      • August 16, 2018

        5 2001 GT - JeremyG Installation Time: Afternoon

        Best exhaust hands down

        Like the title says, it’s the best exhaust system for your 99-04! A very deep and not obnoxiously loud exhaust by itself. But if you pair it with a BBK O/R x-pipe like I did, watch out! It sounds like a monster unleashed! Very deep and actually not too loud at highway speeds, can have a convo. Would highly recommend!

        Helpful (7)
      • April 29, 2018

        5 2003 GT - DanielS Installation Time: Afternoon

        Awesome exhaust

        Sounds so sweet! Very good design and great product.

        Helpful (8)
      • April 02, 2018

        5 2002 GT - Moe Installation Time: Less than 1 Hour


        Omg The difference. I went from a completely stock set up to this catback. No headers, stock H pipe with cats and the sound was still amazing. Highly recommend this. At idle the sound is low enough not to annoy neighbors but once you get on it... wow that rumble.

        Helpful (7)
      • November 25, 2017

        4 2004 GT - peterm Installation Time: Afternoon

        cat back

        nice unit its loud magna flow allmstainlees steel had all connections weilded

        Helpful (8)
      • November 23, 2017

        5 2001 GT - JimBo43 Installation Time: Shop Install Installation Cost: $100-$250

        Great Sound

        Had stock exhaust on my wife's 2001 GT, MAN this cat back exhaust sounds GREAT! Not sure about any increase in HP, but the amazing sound makes it feel like it, LOL

        Helpful (8)
      • November 19, 2017

        4 1999 GT - Donald Installation Time: Afternoon

        Very happy with this exhaust!

        You should add $50 to the price and throw in some hangars and stainless flange studs.

        Helpful (8)
      • August 24, 2017

        5 2004 GT - MarkD Installation Time: Shop Install


        Perfect sound for the Mustang! Even in the convertible, it's throaty, but not too loud! Aggressive and smooth!

        Helpful (9)

      Questions & Answers (18 answers)

      5 Top Rated Questions

      will mac pro chamber work with this i am in the market for an exhaust i am thinking about getting mac long tubes w/ pro chamber and not exactly sure about cat back byt like the sound of the magna pack my question is will all these components work together

      • Yes the prochamber will work with the magnapacks, this is the setup i currently have on my 2000 gt and it sounds amazing

      Helpful (2) Show 1 more answer

      Will this fit a v6 with v6 x-pipe

      • No, this Catback was designed to only fit V8 model Mustangs.

      Helpful (1)

      Is this legal in ct

      • We recommend reaching out to your local DMV or state inspection location for your states laws regarding exhaust regulations.

      Helpful (0)

      would this fit with after market xpipes on a 2004 gt

      • this would fit on your mustang.

      Helpful (0)

      to install this in a 04 Mach 1 would I need anything else like x pipes or would this be the only thing I need to buy for the entire system?

      • Nothing else would be needed for the install no.

      Helpful (0)
      Post Your Question
      10 More Questions
      In my area I have to have cats and a muffler does this have both of those 1 answer
      I'm curious if this cat-back is what people refer to as "Magnapacks" or if they are two different mufflers/set ups. The item is Magnaflow competition series. Is that set up the Magnapacks as they call it or is Magnapacks a completely different set up? 1 answer
      Will this exhaust be able to pass emissions test in California? Does it have a carb #? 1 answer
      Will this exhaust work with a 5.0L Coyote Engine swap? 1 answer
      Will this fit a manual? 1 answer
      I plan on getting this exhaust for my 2003 V6 mustang and was wondering if the Pypes catted X pipe will allow this to fit? With the Pypes catted X pipe and this exhaust will it be crazy raspy like I've been hearing on the Pypes exhausts? How loud would this be on a scale from 1 to 10? I want a head turner, but nothing that is going to get me pulled over. I want a nice deep tone at idle and for it to be heard when I step on it. any help would be GREATLY appreciated. Sorry for the beginners questions I'm just getting started in the pony world. 1 answer
      I live in California and the emmission regulations are strict. Will this competion catback exhaust pass the emmission test? I'm getting the BBK shorty headers, true dual adapter ( I have a v6 ) and these if they pass the emmission test. If not is it better to get the other magnaflow street catback exhaust? 2 answers
      V6? Will these fit the 02 v6 with the pace settler dual exhaust adapter kit? 1 answer
      Will these pypes work with your PaceSetter V6 Dual Exhaust Adapter Kit (99-04 V6) I have a 99 v6 mustang and i want to make my stang into dual exhuast, but i don't want to use the same factory y-pipe set up and i don't want to buy any dual exhaust converter catback systems neither. I want the true dual. WIll this work or should i buy an H-pipe somewhere else and stick those on with the Magnaflow MAgnapack Catback exhuast. 1 answer
      magnapacks vs slp loudmouth II I like the sound of both the magnaflow magnapacks and slp loudmouth II's because they both have a deep aggressive tone. I'm trying to decide between one or the other. As of right now my mustang is bone stock. I like the deep agressive tones but i don't want something that is extremely loud which is the only reason I'm afraid of the loudmouth II's. Which of the two exhuast systems are liuder/would be better suited for me? 5 answers

      Installation & What's in the Box

      Installation Info

      What's in the Box

      • (2) Flow Tubes
      • (2) Tail Pipes
      • (2) Competition Mufflers
      • (2) Polished Tips
      • (2) Set Screws w/ Allen Wrench
      • (2) Tip Hangers
      • (6) 1.25" x 2.5" Band Clamps
      • (2) Header Mounting Flanges

      Tech Specs

      Cat-Back Exhaust Specifications
      Piping Material:Stainless Steel Tip Material :Polished Stainless Steel
      Piping Size:2.5"Tip Size:3.5"
      Muffler Type:Straight-throughFitment:1999-2004 GT, Mach 1, Bullitt

      Will It Fit My Mustang

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

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