Useless someone here has owned and swapped out these pipes, the only responses you'll get is "mine is the best.". You need to find a meet up and see if others will let you take a ride in their car, this way you can make an informed decision.
irickchad said:CatLESS will be much louder, as well as let certain gases pass through the exhaust, resulting in fumes and an often noxious odor if you're behind the car.
XJman said:He means catless.