+1 to snowbird's comment. tho its not just the yosh that his comment would apply to, its really ANY aftermarket setup. the header pipes pretty much stay in place regardless what you do, as I've only seen ONE company that makes aftermarket header pipes (that being Delkevic Exhaust) and honestly, i dont know how effective theyd be. as for buying an aftermarket setup such as a 4-2-1, all youll get is the 4-2-1 baffle that bolts onto the back of the header pipes, the muffler, and the mounting hardware. one thing i can say about the 4-2-1 systems tho, theyre WELL worth it!