carsound is a great price, but like i said.
if you live in a non-smog emission testing area and your cat is done, FTW.
i have one on and i don't have any rotten egg smell. Ray and Andryck have been around my car and no one has ever noticed any smell...
i get the polluting thing, don't get me wrong. but for me it's just price. and $40 would be an expensive test pipe, average is 20