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SLP Loudmouth Axle-Back Exhaust (05-10 GT, GT500)

Market Price $376.95 You Save 4% ($15.00)
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  • Item 23013
  • MPN# M31014-AA

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Features & Details

  • Rich, Throaty Exhaust Sound
  • 3.5" Polished 304 Stainless Steel Tips
  • Fits 2005-2010 GT and Shelby GT500 Mustangs
Super Aggressive Exhaust Rumble. This SLP Performance Parts Axle-Back System eliminates the restrictive factory mufflers entirely from the 2005-2010 Mustangs, drastically reducing back pressure for enhanced power and aggressive sound.

Rugged, Durable Construction. SLP's Axle-Back system is made from 2.5" mandrel-bent 409 stainless steel tubing, which has excellent flow characteristics and features pre-welded hangers for simple installation. The hand polished, 3.5" dual wall tips give a show quality muscle car appearance to the rear of your Pony.

Application. The SLP Loudmouth Axle-Back is designed to fit the 2005-2010 GT, 2008-2009 Bullitt, and 2007-2010 Shelby GT500 Mustangs.

Technical Note: Americanmuscle recommends adding the 2005+ Mustang 304 Stainless Steel Exhaust Hanger Kit from the drop down option above, to provide more strength, stability and a cleaner installed appearance. If you have a 2007 Mustang you may need the kit for correct installation.

Fitment: 2005 2006 2007 2008 2009 2010 Details

What's in the Box
Hardware included:
  • (4) Four Clamps
Installation Info
Tech Specs
Axle-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 / Resonator Fitment: 2005-2010 GT Mustangs
Will it fit my Mustang?
  • Bullitt - 08, 09
  • GT - 05, 06, 07, 08, 09, 10
  • GT500 - 07, 08, 09, 10

People Who Bought This Item Also Bought

Most Helpful Reviews

2007 Shelby GT500

I hesitated buying these because I thought they would be to loud, but I'm glad I got them. Not only is the sound just awesome, but it's not obnixious loud like I originally thought. Don't get me wrong ...

Read More
Helpful (42)

SLP 2008 GT

After doing extensive research into what axle back exhaust to get I finally decided on the SLP Loudmouths. This Truly brings out the sound of your V8. Not to say the stock mufflers were bad, but after ...

Read More
Helpful (35)

Overall Rating 4.9 out of 5 stars
Read All 100+ Reviews

Customer Photos (71) Submit Your Photo

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25 Questions / 5 Answers

Ask a Question

Is the exhaust noise legal for Pennsylvania state inspection as in not a true muffler?


  • PA State Inspection requires at least one muffling device to pass - since the SLP Loudmouth Axle-Back Exhaust eliminate the muffler, these would technically not pass.


Helpful (0)

how badly will this effect my gas mileage??


  • Axlebacks such as this SLP Loudmouth Axle-Back Exhaust will not cause a change in fuel economy as it will only change sound.


Helpful (0)

What’s the difference between these SLP’s and Flowmaster outlaws? Would back pressure be an issue with no catalytic converters?


Will these axlebacks provide back pressure?


  • The SLP Loudmouth Axle-Back Exhaust uses resonators within the tips, so this will provide some back pressure, though it will be drastically less than what is created by the stock mufflers. Your catalytic converters will also cause back pressure in the exhaust, so this should not be a concern, especially on systems still using cats.

    Rob D

Helpful (0)

I'm looking for I loud deep aggressive sound for a 2007 mustang gt would these be a good option?


  • This exhaust is one of the loudest options for a 2007 GT however the sound will have a deeper pitch moreover an aggressive one.


Helpful (0)

I have on my 07 Gt Bbk shorty headers, bbk xpipe, high flow cats and my axle back is what came with Ford. What difference in sound will i get from cutting out the Ford racing axleback to the Slp axle back? More aggressive? Less? Thank you


  • SLP Loudmouth Axle-Back Exhaust provides a much louder open and raspy sound. It is a single muffler chamber muffler which provides a different sound from muti-chamber mufflers

    AM MikeW

Helpful (0)

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Customer Reviews (100+) Write a Review

Overall Rating 4.9

out of 5 stars

Installation Time:Afternoon

Installation Cost:0-$100

  • Loudness / Volume 4.786982 4.8
  • Exhaust Note 4.7929 4.8
  • Fit & Finish 4.674556 4.7
  • Bang For Your Buck 4.621302 4.6

  • 5/5

    April 27, 2010

    2007 Shelby GT500

    I hesitated buying these because I thought they would be to loud, but I'm glad I got them. Not only is the sound just awesome, but it's not obnixious loud like I originally thought. Don't get me wrong they are loud but it's not to much. Chances are if your looking for an exhaust you trying to increase the sound and this is the one you need. Very raspy deep tone and I can tell you first hand it will turn heads. This exhaust will transform the attitude of your ride. Installation was a breeze, however it does take a little bit of time to get them just right.


    Year: 2007 Submodel: GT

    Helpful (42)

  • 5/5

    May 28, 2010

    SLP 2008 GT

    After doing extensive research into what axle back exhaust to get I finally decided on the SLP Loudmouths. This Truly brings out the sound of your V8. Not to say the stock mufflers were bad, but after hearing these things, I don't think I will ever go back. Before it purred, now it spits and pops. Once things heat up it really isn't obnoxiously loud. You can hear it faintly as you cruise down the road, but put your foot into it and watch out! You will not forget they are there! Install was easy. I didn't even have to jack the car up. It might be slightly easier if you do but it's not required. You will notice it is easier to put the SLPs on than it is to take the stock ones off. Alignment can be a little tricky. Make sure you don't tighten everything but rather have it lose so you can position things correctly the first time through. Steve McQueen would be proud of these!

    Douglas Kirk

    Year: 2008 Submodel: GT

    Helpful (35)

  • 5/5

    May 26, 2010

    2010 GT w/ SLP

    Very loud when you step on it but I also passed a couple of police roadblocks with SLPs and they didn't say a word. It truly depends on how you drive. But even when it is quiet it really sound powerful and growly. I'm entirely satisfied with the sound, the delivery and how easy it was to install. I recommend this to any stang addict who'd like a muscle car tone.


    Year: 2010 Submodel: GT

    Helpful (33)

  • 5/5

    May 12, 2009

    Beast Maker

    Hands down a fast way to make your Stang sound like a Stallion on Roids. Order it on the 11th got it on the 12th. Forty five minutes later i am making ricers cry.


    Helpful (26)

  • 5/5

    March 25, 2010

    The Exhaust from the MUSTANG GODS!!!

    If Jesus Christ had a Mustang these are what he would have on it! Amazing sound and LOOOOUUUUDDDDDD! You can hear me coming before you see me and when im gone its like i never left the parking lot!

    Adam DeWitt

    Helpful (19)

  • 5/5

    August 22, 2010


    Just installed the loudmouth today. Had to wait eight days for shipping because I live in canada but it arrived hastle free. Install took around two hours for me, could be done in less for the experienced wrench man. It was easy and when I fired it up ohhhh man it sounds sweet. Just a note if your picky like me you should start with the drivers side first as it helps with alligning the fitting for the other side so they both stick out the exact length. Such a great product and really makes you feel like your driving a muscle car. Now I need more thanks AM

    Josh B

    Helpful (12)

  • 5/5

    Installation Time: Less than 1 Hour

    May 22, 2012


    At first i was hesitant about buying these, i thought they would be too loud inside the car and get annoying at times, but honestly, its not obnoxiously loud inside unless you have the windows down, and it has a great tone to it. I listened to so many youtube videos on this exhaust, but in real life it sounds 100 times better than any video can make it sound!


    Year: 2007 Submodel: GT New Jersey

    Helpful (9)

  • 4/5

    August 04, 2010

    2010 Mustang GT

    Just finished installing my Loudmouths. Installation took a little longer than anticipated because a couple of the exhaust hanger bolts were apparently crossthreaded from the factory. When I went to back the bolts out they were binding and I knew they were crossthreaded. Upon reinstallation of the bolts, they would spin out and could not be torqued down tightly. If this happens to you, a little Loctite Thread Locker will fix the problem. You may also need to grind a quarter to half inch off of the driver side exhaust tip hanger rod. The rod is a little long and will touch the rear bumber frame thus preventing the proper extension of the tip through the rear plastic fender exhaust cutout. Delivery was lightning quick - ordered them on a Sunday and received them Tuesday afternoon! The Loudmouths sound great !


    Year: 2010 Submodel: GT

    Helpful (9)

  • 5/5

    Installation Time: Less than 1 Hour

    September 21, 2011

    This product has a great sound.

    The SLP Loud Mouth exhaust has a great sound if you like the old school muscle car sound. The install was easy and the fit and finish was excellent but I highly suggest the following the instructions and not tightening everything up till last for adjustments.


    Year: 2007 Submodel: GT Charlotte, NC

    Helpful (6)

  • 5/5

    February 11, 2011

    05 Mustang GT

    Rsearched exhaust on this website for many months and couldn't make up my mind...finally i pulled the trigger and bought SLP loudmouth and boy did i make the RIGHT Mustang sounds awesome...has the growl i was looking for...not to mention the amount of people who stop and stare as i go by...if you like attention this is the exhaust for you...easy to install...took about an hour....thanks american muscle...

    Joe V

    Year: 2005 Submodel: GT

    Helpful (6)

  • 3/5

    April 17, 2010

    Not what you think

    These are not an exhaust system. These are nothing more than straight pipes with no muffler. Do they sound good? Of course they do, its a mustang with straight pipes. However, this is not near worth the price considering you can have the same thing done and any muffler shop for the price of $20 stainless tips and about $50 straight pipe and labor. Good quality, great sound, WAY to expensive for what you get.


    Helpful (6)

  • 5/5

    Installation Time: Less than 1 Hour

    September 06, 2012

    Classic Mustang throaty Sound

    I just got my SLP loudmouths and I am very pleased. The fit and finish were top notch. Installation actually took me about 2 hours but that was because I was interrupted about 10 times during the install. The hardest part of the whole installation was getting the old mufflers off. Once installed, the magic begins. The sound is absolutely gorgeous. I was worried at first because of all the online videos make them sound terrible. I can say right now that these videos do NOT do any justice for these pipes. While I thought the price was a little steep, it is nowhere near as high as other brands. If you are budget minded and looking for that old school sound, then worry no more. Buy these axle back pipes. You will be glad that you did.


    Year: 2007 Submodel: GT NC

    Helpful (4)

  • 5/5

    Installation Time: Less than 1 Hour

    January 31, 2012

    Extremely easy installation.

    I listened to the online sound bites several times. I read most of the reviews and picked these exhaust pipes. The reviews were very helpful. I had to cut about an inch off the hanger on one side (as I had read in the reviews). I also followed anothers advice regarding connecting it all, but not tightening the clamps UNTIL I was satisfied with the alignment. GREAT PRODUCT, AWESOME SOUND ! I had a 2011 - 5.0 pull up beside me at a light and tell me that it sounded GREAT !


    Year: 2006 Submodel: GT South Carolina

    Helpful (4)

  • 5/5

    June 15, 2011

    Everything I hoped they'd be

    I looked around a lot on youtube for sound clips of different axle backs and I finally decided on the SLP Loudmouths. Let me tell you, they sound INCREDIBLE! Definitely the best axle back out there. Install was very simple. Just unbolt the stock mufflers and the bolt up the slp's. The most difficult part would probably be reaching the bolts on the exhaust hangers. Other than that everything else was a piece of cake. Lining up the pipes were a little difficult too but it just takes some elbow grease and patience. The sound is deep and throating and at 3,500 rpm and up it sounds amazing! Drone isn't too bad but if you worry about drone then why are you getting a loud exhaust anyway? Overall this product was definitely worth the money! You wont be disappointed whatsoever. I know I wasn't. Next I'm going to get a Magnaflow catted x-pipe which will sound great. Hope this review helped!

    Mike Bruno

    Year: 2006 Submodel: GT

    Helpful (4)

  • 5/5

    March 24, 2010


    Awesome product. Very easy install and sound tough. Much better than flowmaster and borla. Worth the money for sure.


    Helpful (4)

  • 5/5

    March 01, 2010

    Thunder from your pipes!

    Really opens up the note from stock or even an aftermarket setup. 3~4k rpm sounds like god letting one rip after chilli night!

    Mike K

    Helpful (4)

  • 5/5

    March 20, 2010

    Lovin LOUD

    Well was not sure I wanted to go loud like Brick stated they would be. However I made the best choice by going with the SLP rocks the neighbors windows and my garage. Mate this up with the BBK 62mm throttle body and a Roush cold air intake..yeah this Stang turns heads and brings back the American spirit of pony power. If your ordering choose the 3 day shipping, it took seven days to get to Cali from PA.

    Jason G

    Helpful (3)

  • 5/5

    March 09, 2010

    Amazing Exhaust

    Great exhaust,install was easy...didnt even have to jack up the car. Sound is amazing!!! the idle is nice and gurgly and once you hit 2-3k+ it is freakin awesome.

    Tony N

    Helpful (3)

  • 5/5

    Installation Time: Less than 1 Hour

    July 29, 2014

    Stock car sound

    Paired up with an pypes offroad x pipe watch out, your neighbors will not like you what so ever with this set up. Extremely loud when you are into the gas but if you feather the throttle you'll manage to get by. First night I had them I went ratting around to see how loud it would be at night time and after my driving session my ears were hurting. When you get into the throttle it sounds like a stock car and that is no joke. If you want a mean sounding mustang that will turn heads wherever you go then this is the set up for you. It sound MEAN. I highly recommend this product.


    Year: 2005 Submodel: GT Michigan

    Helpful (2)

  • 4/5

    Installation Time: Afternoon

    June 28, 2014

    Sounds brutal!

    It took me about an hour and a half at the auto skills center. The fit could have been better, but I'm sure it's my fault. The sound is brutal! It turns heads everywhere and I love it!


    Year: 2007 Submodel: GT500 Ft. Lewis

    Helpful (2)

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