There are actually 2 types of cats for 96+ GSRs. One is for california spec cars other is for the other 49 states. The cali-spec one will not bolt to a non-cali car. Trust me, I went through this a year ago and it was a distaster. Although I am begining to think that most cars out there are california-spec because I have only heard of a few people having this problem. Carsound (magnaflow) makes the california one and there are some companies out there that do make a non-cali one. If you really need to know I can look up where I ended up getting mine from.