I have changed the exhaust on my 05,10, 13, and 15 .Never had any warranty problems from the dealer . In fact the dealer installed an x pipe on the 05 ,roush catbacks on the 10 and an h pipe on my 15 . I ,personally, believe that Ford expects us to alter some things because that is really a part of the Mustang Lifestyle.

 

I had a hard time deciding on a new exhaust for my 2015 GT, but ultimately went with the Roush AB. I have been driving it for one week now with the new exhaust, and I LOVE it! Not too loud and not too quiet; just right. My daughter comments on it every time she gets in the car. :-) I kept the original exhaust, just in case.

 

I had a local Ford dealer install the Ford Performance Touring Catback exhaust system on my 2015 Mustang GT (exhaust made by Borla). This configuration does not void the warranty. I like the sound, maybe a little to aggressive during hard accelerations, but I get noticed at intersections... Sounds great idling. With hindsight, I might have settled for just the axle back mods.

 

I made an appt. with my Ford dealer to install my Roush AB, but because the original exhaust was welded on, they wouldn't touch it. They thought that it would be a simple task, that didn't require a sawzall. However, they recommended a local exhaust shop, and so I took it there. The guy was super nice and had it done in 40 minutes. The salesman that sold my car to me just put a Borla exhaust on his '08 Mustang. Of course, he had to start it up for me. It was definitely loud! He loves it!