Mine is open from the headers back 2.5 untill the mufflers some cheap ass ones I bought from ebay 3 years ago. it has a low ruble like a v8 at idle ( sound awesome) and a very loud wot at open throttle . Makes the na sound faster than it really is. when you blip the throttle it sounds good as well but that highway driving can get old fast. most times I enjoy it & other times I wish it was stock espically for those long trips. I have a lot of people like it & just as many not like it. deffinatly the only z Ive ever heard sound like mine is mine. no one has been as adventerous Or stupid to do what Ive done that Ive ever heard on any other z.