2024-2025
2015-2023
2010-2014
2005-2009
1999-2004
1994-1998
1979-1993
Installation Time
(approx) 2 Hours
Difficulty Level:
Light to Moderate mechanical skill required.
FREE 1 to 3-Day Delivery on Orders $119+ Details
Talk to a Mustang Sales Tech
1-877-887-1105
M-F 8:30A-11P, Sat-Sun 8:30A-9P
Find Cat-Back Exhaust for your Mustang
SLP Loudmouth Cat-Back Exhaust (99-04 Mustang GT, Mach 1)Find parts that fit my vehicle
Item 23001
$0.00
500+ Reviews
58 Answers
Our Price
$598.49
Ship to: 43215
Please enter a valid US or CA postal code
We're sorry, zip can't be updated at this time.
Will this fit your Vehicle?
Saved - View your saved items
We're sorry. We couldn't save this product at this time.
or use
Add Local Installation
$299.00
Frequently Bought Together
Product Information
Features, Description, Reviews, Q&A, Specs & Installation
Features & Specs
- 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 1999-2004 GT, Bullitt, & Mach 1 Mustangs
| Brand | SLP |
| Exhaust System Type | Cat-Back System |
| Exhaust System Material | Stainless Steel |
| Exhaust System Tip Finish | Chrome, Polished |
| Exhaust System Tubing Diameter | 2.50 Inch |
| Exhaust Loudness | Aggressive |
Description
More Power and Sound. This SLP system includes SLP's infamous Loudmouth "shotgun" race resonators that offer virtually zero flow restriction to free up more power 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 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 extra modifications required on the 1999-2004 GT, 2001 Bullitt, or 2003-2004 Mach 1 Mustang to give it a rich, throaty sound.
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 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 extra modifications required on the 1999-2004 GT, 2001 Bullitt, or 2003-2004 Mach 1 Mustang to give it a rich, throaty sound.
SLP M31007
CA Residents: 
WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov
Installation & What's in the Box
Installation Info
What's in the Box
Hardware included:- (2) Intermediate Pipes
- (2) Over-axle Pipes
- (2) Resonators
- (2) Tailpipes
- (2) Tailpipe Tips
- (8) Clamps
- (2) Ball Flanges
- Instructions
Tech Guides:
4.9
Customer Reviews (500+)
Questions & Answers (58)
Will It Fit My Mustang
- Bullitt - 01
- GT - 99, 00, 01, 02, 03, 04
- Mach 1 - 03, 04
Fits GT, Mach 1, and Bullitt
