A Mustang that doesn't inflict at least a mild sense of fear in the cars around it is likely not a Mustang at all. One of the best ways to put a grin on your face and ensure those around you know what kind of power is under the hood is by modifying the exhaust. 2015 Mustang exhaust parts like headers, X-pipe and H-pipes, axle-backs and complete exhaust systems should be one of the first areas to modify as modifications like these can yield fairly hefty power gains while molding your exhaust note into whatever type of rumble you're after.
These guys are great! Customer service is absolutely top notch. Their pricing points are spot on and every month they off some sort of special on multiple parts. Not only that but the staff will educate you on the parts and their customer reveiw option of every part has been a huge help in determining the validity of each part you buy. American Muscle is the perfect example of what a full service parts distributor and custom tuning shop should be. I'm just glad they are Mustang exclusive!