you will see similar results from all of them. more increase if you do both exhaust and headers rather than one or the other. Headers typically need to be regularly tightened so they dont leak. Banks claims to have better alignment over the ports and less leaking issues, but I say claim as I have not used them. they carry both exhaust and the headers which at least will be designed together but you pay a premium for their stuff. their info is at www.bankspower.com. I have a magnaflow exhaust and like it. it isnt a loud exhaust but that keeps the wife happy and I dont notice the drone that some complain of. I am looking at headers this summer but have not decided on edelbrock or going more expensive with JBA or Banks.