ok I hear the 90 integ gs exhaust will not fit on the b16 ex. manifold without some modification. where can I order a catback exhaust that will fit my engine and car? I would like to have a thermal r&d exhaust. do they make one that will fit my engine and car (right out of the box) thanks in advance.
To the best of my knowledge exhaust systems connect to your cat or your straight pipe and doesn’t connect direclty to your ex. manifold. If you want a cat back system you just tell the company your year, make, model and whether or not it’s a 2dr or 4dr!
:think: I hope that helps! 
If you use an LS header, you shouldn’t have any problem, the B16 header is about 3" shorter then an LS one I believe.