I just replaced my cat which was last done in 92-93. When I pulled it off, a socket wrench fell out of the back of it, left by the dealer's tech! (pays to do things right yourself) I'm seeing much better mileage and drivability, and way more power.Turns out the old cat was swelled in the output end, probably made worse by that wrench concentrating heat.

 

Just getting money together and waiting for a nice Saturday to put in a straight pipe. may be a while though