i got a buddy who has a set of SHM long tubes and matching h-pipe with high flow cats for sale. he wants 800$ for them, they look like a very high quality header. he claims that they are the best for the 4 valve motors, and up to a 50 hp gain for me on my whippled '03. what i am wondering is 800 a good deal for them? and are they that much better than like a bbk or mac header. just kinda hard to justify 800 for used headers plus he says i will need the car retuned...im foggy here thanks for the input guys.