Just upgraded to the flowmaster american thunder system. This is the same system I had under my 13 R/T. It sounds a crap load different on this car than it did on the 13, a lot crisper, don't know the difference but there is a noticeable sound difference. I parked it right next to my old one and we lit them both up, the shaker sounds a ton better. On another note, the factory exhaust on the Shaker, and probably the 14s across the board is different. It is one piece all the way back and does not come apart in sections (no welds, just straight pipes). Appears that the mufflers and resonators are slightly different over 13 as well.