I drive a 96 civic dx auto i have i/h/e. When i installed the headers i removed the cat and now want to possibly install a replacement aftermarket cat intendeed for an integra. Will any fit? O2 sensor bung? I believe my inlet and outlet would be 2.5". If none do how much would a shop charge my to weld one into my current exhaust piping? My car is way too loud for my taste and i have been looking for a solution for awhile now puting a cat back on seems like the best choice any help would be alot. Thanx