02 GT

Buy a pair of cats (one per side) and get an exhaust shop to weld them in. As long as the car is well warmed up you should pass emissions.

First red flag is Long Tube Headers. Illegal in CA. You'll also need CARB sticker or proof of the TB and CAI E.O. giving it acceptance in CA. You need 4 Cats on the exhaust. You also need 4 O2 sensors. Each side has one before first Cat and one after second Cat. Easiest thing to do is find a exhaust section that has been removed or buy new and not guess. However, they WON't fit long tube headers so those need to be changed. Of course, if you for some reason have a CARB E.O. for those headers, great (but I doubt it). Sorry.