Mine is donated from "a truck". Had to be done after a hollowed out cat was discovered after failing emissions horribly when we got the car.
Old cat cut out, new one sectioned in.
Lasted four years, and then the area in which it was joined broke just a couple weeks ago, causing the exhaust to be open and hanging down just behind the cat. I'm surprised my ears didn't bleed. But hey, dad and I went home, he plugged in the welder, rejoined the pipe, and bzzzzzzzzzzzt. Not the prettiest solution, but it'll hold.
This cat gives me resonance right below 2000rpm - just a bit *different* from other Vin C 3800'* I hear. I think it might be akin to that of a 3800-powered Grand Prix, only considerably louder. I wish I could tell you the donor car.