Hey one of my buddies is going to do stacks on his truck and he needs to know what parts to get. He has an extended cab shortbed, and wants the stacks to be a y in the bed. He is going to have 4" stacks and has 3" exhaust. He wants them to look real clean cause he is not going to put a tool box in. Could we get all the parts at a local TruckPro? Besides the stacks what would the pipes have to be to not rust or discolor... stainless steel? Oh and the dealer can't dishonor his warranty if we take off the muffler and cat right?