hey sorry ive been really busy at the shop. on the 3.5 i need to find one and use it for a proto, i just have mine so i got into it. i actually sent a set of stock manifolds to a guy that builds headers for street rods, and he is in the process of flow testing stock, and fabricated and dyno working on new ones. the set i just got lost a litle tq but bumped the high end by 3.5 HP but lost 1.2 lbs TQ, so he is making a new pair to remedy both. were shooting for 5 HP gain across the board. so im holding on the cat backs so i make sure i can have them bolt on to the exhaust with no mods to it. im thinking next month. if you wanna stick with the stock manifolds i can do a street legal cat back for 120 with a holly rapter muffler. its chamberd, mine sounds like a toyota tundra with a flow master using this muffler. if you want a straight through like a flowmaster it would be 150. but i have lots of mufflers to choose from, tell me what you want sound wise. and any mods you have, i can can give a list of options. were not so busy right now so i will be on here regularly. we had alot of cars from sema come in and had us swammped. i thnk were the only exhaust shop that was open till 10pm just to keep from cars pilling up.