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SLP Loudmouth Resonators - Pair (79-04 All)

100+ Reviews
Our Price


  • Item #23032
  • MPN# 31062

  • Market Price $154.95
  • You Save 4% ($6.00)
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  • Loud Aggressive Sound
  • Virtually No Restrictions for More Horsepower
  • Designed for SLP Modular Cat-Backs
  • 2.5" Inlet/Outlet Diameter
  • Hand-Polished 304 Stainless Steel
  • Sold as a Set of Two
More Power and Sound.   These SLP Loudmouth "shotgun" race resonators are designed to have virtually no exhaust flow restrictions to free up more power and to produce the most aggressive sound possible.

SLP Modular Design. SLP manufactures their Mustang catback exhaust systems with a unique modular design that allows you to easily and quickly swap out the included mufflers with any of the other SLP mufflers or resonators they make to suit your driving needs.

High Quality Construction.   The Loudmouth "shotgun" resonators are constructed from hand-polished 304 stainless steel and are embossed with the classic SLP logo. They have a high flow design and measure in at 2.5" ID/OD, 4.5" Body Diameter, and a 18-3/16" Overall Length.

Application. These SLP Loudmouth Resonators are designed to easily replace the existing mufflers or resonators in any of SLP's 1979 to 2004 Mustang Cat-Back exhaust systems. The may also be used in the fabrication of custom exhaust systems.

Fitment: 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 Details

What's in the Box
Hardware included:
  • None - reuses stock hardware
Installation Info
Tech Specs
  • 2.5" ID/OD
  • 4.5" Body Diameter
  • 18-3/16" Overall Length
Will it fit my Mustang?
  • Bullitt - 01
  • Foxbody - 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93
  • Mach 1 - 03, 04
  • V6 - 94, 95, 96, 97, 98, 99, 00, 01, 02, 03, 04
  • Cobra - 94, 95, 96, 97, 98, 99, 01, 03, 04
  • GT - 94, 95, 96, 97, 98, 99, 00, 01, 02, 03, 04

Most Helpful Reviews

Amazing Sound and Performance, Excellent Price!

Ordered them on a Wednesday night, and got them by Saturday morning. Crazy loud and unbelievable exhaust note. Works extremely well with an O/R X-Pipe.

Helpful (3)

SLP 1 Resonators

I just had these resonators installed to replace the stock mufflers. I still have the stock manifolds and stock h-pipe with the 6 cats. After doing a ton of research and living in a emissions sensitive ...

Read More
Helpful (4)

Overall Rating 4.9 out of 5 stars
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31 Questions / 16 Answers

Ask a Question

Can these be fitted on a 99 v6 with a gt exhaust? My car is a 99 v6 with a gt exhaust equipped on it. Can i weld these on here? Thanks!


  • Absolutely. As long as you have dual exhaust with 2 mufflers, then you can have these welded on.


    Good Answer (1) (0)

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What would happen of I welded these in and kept my stock mufflers in?


  • There would be no reason to keep your stock mufflers in. These replace the entire muffler for the exhaust system. If you left your stock mufflers in, you could possibly hurt your mustang's performance. The exhaust system is not designed to have 2 mufflers for each tailpipe. Just bring you SLP Loudmouth Resonators to any reputable mechanic shop and have them weld these in. They will know to remove the stock mufflers and your mustang will sound AMAZING!


    Good Answer (7) (0)

Show 2 more answers Question Resolved

Foxbody Mustang 88 I have a 1988 foxbody 5.0 with bbk shorty headers/bbk off road h-pipe/ and super 44 flowmasters, and I know this would make my fox louder but would I see negative effects resulting from back-pressure loss?


  • You won't have any real problem with back pressure. Being as how you have shorty headers your back pressure will be sufficient to run properly with good power.


    Good Answer (1) (0)

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will these sound good on a 2000 v6 mustang I began with a dual glass pack and it sounded like a ricer so i cut those off and put in flowmasters and you really dont hear anything until you floor it. so im looking forsomething that sounds good but still pretty LOUD!!!!!


  • these will sound identical to the glass pack set up you had before they are nearly an identical style just straight through with very little sound dampening material inside of them


    Good Answer (0) (0)

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Can i put these on a stock V6 ? I just bought my stang and wanna add an agressive sound, everythings stock right now, but if i get these SLP loudmouth's would it work well ? My stangs only got one exhaust, not the biggest car geek but need some advice


  • 98V6, You can, but they are obnoxously loud. If that is what you want, then you're fine. I would first look at getting a true dual exhaust on the car. AM offers a FlowMaster kit specifically for the 1998 V6.


    Good Answer (0) (0)

Show 4 more answers Question Resolved

SLP LM1's vs Pypes M80's??? I have a stock exhaust system on my 89 GT vert and I was looking for a more aggressive tone for it. I don't have the money to buy a new aftermarket exhaust so I'm looking at the SLP LM1's or the Pypes M80's. Which will give me more bang for my buck? I will be dumping the exhaust directly off the mufflers.


  • I have had both and in my opinion the slps are more aggressive.


    Good Answer (0) (0)

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Customer Reviews (100+) Write a Review

Overall Rating 4.9

out of 5 stars

Installation Time:Full Day

Installation Cost:0-$100

  • Loudness / Volume 4.795181 4.8
  • Exhaust Note 4.795181 4.8
  • Fit & Finish 4.819277 4.8
  • Bang For Your Buck 4.746988 4.7

  • 5/5

    July 27, 2016

    Absolutely worth It

    Totally worth the money, sounds beautiful, turns heads everywhere and get a lot of compliments


    Year: 1999 Submodel: GT

    Helpful (1) (0)

  • 5/5

    Installation Time: Shop Install

    July 03, 2016

    Extremely Loud

    I installed SLP lm1 with reonator cats deleted "straight pipes" and it was extremely loud. In1200RPM loud My Stang was stock only SR cold air intake and it's sounds like stroker.


    Year: 2002 Submodel: GT

    Helpful (1) (0)

  • 4/5

    Installation Time: Less than 1 Hour

    May 31, 2016

    Great Sound

    Just what I wanted. I had some flowmasters but wasn't really happy with the sound. The SLP resonators sound bad to the bone. Keep in mind they are designed to fit into the SLP cat back system.


    Year: 1993 Submodel: Other

    Helpful (1) (0)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: 0-$100

    February 08, 2016

    Sound Amazing

    I was looking for a replacement for my flowmasters 40 series because they were too quiet. I was hesitant to buy these because of the price, but I am very happy that I did! It sounds so much better than it did and is now much more enjoyable to drive! It is now a real head-turner and sounds much more aggressive without being too loud.


    Year: 2003 Submodel: GT Washington Mo

    Helpful (1) (0)

  • 5/5

    Installation Time: Afternoon

    April 20, 2014

    Slp is the best

    I love the sound these gave my fox I had flowmasters before but they just weren't enough.


    Year: 1993 Submodel: GT Germany

    Helpful (1) (0)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: 0-$100

    June 22, 2012

    Fate led me to these.

    So I had ordered the M80 mufflers because of the price point, yet once I placed the order I found out they were on backorder. Taking this as a sign of fate, I cancelled that order and placed a new one for these SLP's. BEST DECISION I'VE MADE HANDS DOWN. I was worried about them being overly loud, but their tone and volume are perfect. I had a shop install them for $60 and it took 20 minutes tops. I just had these welded into my 100% otherwise stock exhaust system and am so thrilled with how it makes my '01 cobra sound. BUY THEM!


    Year: 2001 Submodel: Cobra

    Helpful (1) (0)

  • 5/5

    Installation Time: Less than 1 Hour

    March 03, 2012

    Amazing Sound & Finish!

    For those whom are skeptical on purchasing these SLP's, no need to worry! The sound is amazing over previous Magnaflows. Setup on stock (4) catted, BBK X-pipe, SLP Resonators, not overly loud; and with an perfect down rev sound. For those of you thinking twice, look no further. Once they were installed, I simply could not keep a smile off my face as I drove for miles on end. I cannot wait to see how much better it would sound with an O/R setup. Just as always, American Muscle has been outstanding with their service, and received within one week time on the west coast. AM, look forward to seeing me again soon!


    Year: 2001 Submodel: GT Southern California

    Helpful (1) (0)

  • 5/5

    Installation Time: Less than 1 Hour

    September 21, 2011

    Amazing Sound and Performance, Excellent Price!

    Ordered them on a Wednesday night, and got them by Saturday morning. Crazy loud and unbelievable exhaust note. Works extremely well with an O/R X-Pipe.


    Year: 2002 Submodel: GT San Angelo, Texas

    Helpful (3) (0)

  • 5/5

    March 21, 2011

    SLP 1 Resonators

    I just had these resonators installed to replace the stock mufflers. I still have the stock manifolds and stock h-pipe with the 6 cats. After doing a ton of research and living in a emissions sensitive state (MD) I was really excited to put these SLP's on my 1996 GT. After having them installed by an exhaust shop, I couldn't wait to turn the key! And then..... Where's the sound? They were only slightly and I mean slightly louder than stock. It looks like the 6 cats are working overtime to keep the exhaust note down. Rats!


    Year: 1996 Submodel: GT

    Helpful (4) (0)

  • 5/5

    December 30, 2009


    it doesn't get any nastier sounding than this..i'm not pushing my hp yet, but if i heard me coming down the road, i wouldn't wanna race me haha..amazing sound when added with offroad x-pipe


    Helpful (2) (0)

  • 4/5

    December 22, 2009

    2000 GT

    I put these on my 2000 gt. i have ford racing shortie headers, magnaflow o/r x-pipe, with loudmouths. i was expecting it to be too loud but they sound really good. the only time it is too loud is when you put the pedal to the floor. i have very pleased with the louthmouths! good buy! thanks AM


    Year: 2000 Submodel: GT

    Helpful (1) (0)

  • 5/5

    November 19, 2009

    Slp resonators

    I had the flowmaster cat back system in b4 on my 02 GT but wanted something louder so I bought these and they are perfect! they sound Loud and mean! AM is the best when it comes to mustangs!


    Year: 2002 Submodel: GT

    Helpful (2) (0)

  • 5/5

    September 27, 2009

    97 GT

    Was tired of having that stock sound out of my V8 and really didn't know what mufflers to go wit, everyone has flows so I wanted to try the slp's and man!!! It is by far the best descion I have made for my stang!!! The sound is so crazy!!! I wake up my neigbors n scare everyone when im flying by the highway!!! Awesome product!!! Thanx AM!!!

    Felix Flores

    Year: 1997 Submodel: GT

    Helpful (1) (0)

  • 5/5

    August 11, 2009


    I purchased the SLP LM2 Catback last summer I ordered the SLP LM1 Resonators last week and put them on today... THESE ARE AWESOME! The LM2 are slightly deeper with a more low growl The LM1 are slightly louder, with a very slight rasp and a WAY more open feel So if you are thinking about these and are worried they will be too loud or too raspy...THEY ARE NOT...Go with these (SLP LM1) and you wont be disappointed...I cant wait to hear what my Magnaflow Catted X will sound like when I put it on at the end of the month!!! SLP ALL THE WAY!


    Helpful (1) (0)

  • 5/5

    February 17, 2009


    I had Flowmaster 40s with a dump on my 97 GT, and it sounded nice and all dont get me wrong, but I wanted something louder. Found it! I looked into Borla Stingers and Magnapacks, they were way too expensive. These Loudmouths sound just as good for a fraction of the price. They are the best!


    Year: 1997 Submodel: GT

    Helpful (1) (0)

  • 5/5

    February 02, 2009


    swapped out my flowmasters for these, couldnt have been a better decision.


    Helpful (2) (0)

  • 5/5

    January 15, 2009

    Great price

    These resonators make your Mustang sound sick. They are extra loud, and for the price you cant get much better.


    Helpful (1) (0)

  • 5/5

    May 15, 2008


    I love Flowmaster, but I found my new favorite mufflers!

    TONY 2002 GT

    Helpful (1) (0)

  • 4/5

    July 16, 2010

    Sounds wicked good

    Ordered these and custom fit them to my 2004 Mustang GT. All other exhaust is stock. Sounds excellent deep throaty sound. NOTE: these resonators are shipped in 2.5" diameter. Stock Mustang exhaust is 2.25" diameter. You will need to purchase increasers.


    Year: 2004 Submodel: GT

    Helpful (4) (1)

  • 4/5

    June 20, 2010

    SLP loudmouth 03 Mach 1

    Just got these and had them installed on my 03 Mach 1. Had them welded on at a local Midas shop. Besides the SLP, everything on the exhaust was stock. Sounds great and aggressive. Very pleased.


    Year: 2003

    Helpful (10) (3)

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