im looking into getting one. where i live we have reformulated gas. i heard these can kill your cat. also, im kinda on a budget. so i was looking at these. http://www.kteller.com/store/index.php/cPath/23_25
which do you think i should get? my piping is 2.5 inch and ill be picking up a dc sports header probably.
if i get one for an o2 bung they come threaded right...

 

I have the 2.5 inch carsound cat. I ordered from kteller with the optional o2 bung. Quality is excellent, no CEL, and I'm being friendly to mother nature.