So what exactly is the difference between LS/GSR/ITR exhausts exactly?
I've got a 98 RS, will an ITR header fit on my car? ... if so, and I keep my stock cat, what catback would fit on my car? I know theres a difference between GSR/ITR/LS catback systems but what exactly is the difference, and is the difference small enough that a modification can be made to make them interchangable? If so, what would need to be changed?