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SLP Loudmouth Cat-Back Exhaust (1998 GT, Cobra)

Item 23006
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      Review & Installation Video

      Product Information

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


      • Rich, Throaty Exhaust Tone
      • Loudmouth "Shotgun" Race Resonators Included
      • Versatile Modular Design
      • 2.5" 409 Stainless Steel Tubing
      • 3.5" Polished 304 Stainless Steel Tips
      • Fits 1998 GT and Cobra Mustangs


      More Power and Sound. This SLP system includes SLP's infamous Loudmouth "shotgun" race resonators that offer virtually no exhaust flow restrictions to free up more horsepower and to produce the most aggressive sound possible.

      Modular Design.   SLP's unique modular design allows you to quickly and easily switch out the mufflers or resonators to suit your driving needs. Along with the included resonators, the Loud Mouth system is compatible with all SLP mufflers and resonators including the bullet-type Loud Mouth II and the traditional-style PowerFlo Muffler.

      Superior SLP Construction. This SLP Cat-Back system is made from mandrel bent 2.5" 409 stainless steel tubing for its excellent non-restrictive flow characteristics and long life. The system ends with a brightly polished 304 stainless steel 3.5" tips, that are electro-marked with the distinctive SLP logo, giving a great finishing touch and a show quality look.

      Application. Designed to be a direct bolt on, this SLP Loudmouth catback will bolt straight up to the factory Mid-Pipe without any modifications required on the 1998 GT or SVT Cobra Mustangs to give it a rich, throaty sound.

      Fitment: 1998 Details

      MPN# M31011

      CA Residents: WARNING: Cancer and Reproductive Harm -


      Customer Reviews (28)

      Write a Review

      Ratings Summary

      5.0 out of 5 overall rating from 28 customers

      Installation Time: Afternoon

      Installation Cost: $100-$250

      • March 27, 2020

        5 1998 GT - Alonso84 Installation Time: Less than 1 Hour

        You can hear us coming

        Great sound! Love the roar of the car now really came alive. It’s a drop top and it sounds awesome!

        Helpful (0)
      • December 25, 2018

        5 1998 Cobra - Bombard32 Installation Time: Less than 1 Hour

        SLP Catback

        I recently installed the SLP Catback system on my 98 Cobra. The fit was perfect! I can't comment on the sound of it yet because I won't be firing up the Cobra until spring. However, I'm sure its going to be very loud considering I have it paired with an UPR x-pipe! It does look very aggressive under the car. A lot meaner looking then the wimpy factory tail pipes. I would recommend this system just because of the looks it provides alone!!

        Helpful (3)
      • June 20, 2018

        5 1998 GT - Matt Installation Time: Afternoon

        Very loud!!

        Great fit.easy to install,looks geat,sounds great!

        Helpful (5)
      • June 06, 2018

        5 1998 GT - GarrettM Installation Time: Afternoon

        SLP LM1

        Has an awesome tone, install only took about 2 hours with no issues or confusion, and is a great start to putting a whole new exhaust system in!

        Helpful (6)
      • March 08, 2018

        5 1998 GT - TravisS


        They were easy to install and they sound amazing and over all they look really good on the car

        Helpful (5)
      • December 18, 2017

        5 1998 GT - BrettR

        SLP Loudmouth

        Pack very well!! Looks awesome can't wait to install!

        Helpful (8)
      • December 07, 2017

        5 1998 GT - DennisS Installation Time: Afternoon

        Love it

        Looks good and sounds amazing. Easy install tips look great. All together took about 1hr 30 mins

        Helpful (5)
      • October 22, 2017

        5 1998 GT - TylerH Installation Time: Shop Install Installation Cost: $100-$250

        Slp loudmouth exhaust

        I love it and it has a deep sound ,when u gas on it it gets louder or u can crip around and hardly hear it I love the way it sounds.

        Helpful (8)
      • October 01, 2017

        5 1998 GT - Phillip Installation Time: Afternoon


        Doesn't come with new flange bolts (3/8) but it's a amazing cat back system. Would recommend to a friend.

        Helpful (6)
      • April 26, 2017

        5 1998 Cobra - QuintonT Installation Time: Less than 1 Hour

        Great Choice!!!

        SLP Loudmouth was a great choice! It's pretty loud and will draw attention. I debated on getting it for a few months because of its loudness, but decided to dive right into it. I am even more excited to drive my 98 Cobra now because it's extremely loud sound. It's worth every cent and the quality is great!!!

        Helpful (6)

      Questions & Answers (10 answers)

      5 Top Rated Questions

      How much HP will it add?

      Do I have to buy something else to install in my car? My car is stock

      • Designed to be a direct bolt on, this SLP Loudmouth catback will bolt straight up to the factory Mid-Pipe without any modifications required on the 1998 GT or SVT Cobra Mustangs to give it a rich, throaty sound.

      Helpful (0)

      I have this system, I’m looking into a maximum motorsports Panhard Bar. Will it clear?

      • We have not yet test fit this combination and are unable to confirm co fitment.

      Helpful (0)

      Will this exhaust fit a 97 Cobra swapped new edge (99 GT) with a BBK O/R X pipe ?

      • This part has not been tested on this kind of swap for confirmation on fitment.

      Helpful (0)

      Will this fit a 1995 gt

      • Unfortunately this exhaust will not fit a 1995 Mustang GT. It will only fit the 1998 Mustang GT and Cobra models. However, we do offer a SLP loudmouth exhaust for the 94-97 Mustang GT models which can be found here:

      Helpful (0)
      Post Your Question
      5 More Questions
      Will this fit with an bbk o/r h pipe? 1 answer
      Can you fit flowmaster mufflers on this catback system later on after you purchase it and put it on the car? 1 answer
      Will this fit a 98 mustang with a 5.0 swap? 1 answer
      will this cat back exhaust turn on my check engine light? im keeping my factory mid-pipe. 1 answer
      Will these fit with long tube headers and a shorty x pipe or will I have to get a mid x pipe? 1 answer

      Installation & What's in the Box

      Installation Info

      What's in the Box

      Hardware included:
      • (4) stainless steel band clamps

      Tech Specs

      Cat-Back Exhaust Specifications
      Piping Material: 409 Stainless Steel Tip Material : Polished 304 Stainless Steel
      Piping Size: 2.5" Tip Size: 3.5"
      Muffler Type: Straight-through Fitment: 1998 GT and Cobra Mustangs

      Will It Fit My Mustang

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