Okay so i want to put a stock itr catback on my ej coupe... i found usdm ones as well as jdm ones... wondering what the difference was because i found usdm for like 200 bucks around, but jdm for 300, and it was from a guy i kinda know. so anyway, he says jdm is wider piping diameter... and also i know that it's not a bolt on mod, but i want to know if it's easy to custom fit or not? keep in mind this is a ej coupe. i'm going to do a more thorough search now, thanks in advance guys.