i have a 1998 gsr db.. and my cat now is going to all sorts of hell.. i removed all of the heatshield b/c of prior noise.. but now i think the cat has just gone bad perhaps from age and high rev straining.. anyhow, i am thinking about a full exhaust changeover? actually maybe just a new cat or something?

i know that my car has 2 oxy sensors.. i think one in the header and one in the cat? so what do i do? i dont want much trouble.. just no more noise...

what im asking is where to get a cat i suppose? i am also considering a apexi ws2 catback.