Alot of people say the EDGE stuff is hard to beat with all the digital monitors...but I've heard nothing but bad things about them actually working and lasting long. If you want what they call good "Bang for your buck" get the Diablo sport predator...if you want a good all around product get the PPE. And some people say that if you delete the cat it will and some say it won't...I basically think it depends on your truck. I decided not too because I don't want to take any chances with codes...but then again I'm a wuss. Plus I had a couple diesel mechanics tell me that a Turbo back system really doesn't do much to a duramax engine...but that's their opinion.