for all of you guys with custom exhaust setups do you buy a new presilencer/resonator, do you use the one that came from your car, or do you just use straight piping from the cat.? does it make it crazy loud if it is just piping? right now i am thinking about using mandrel bent piping from Magnaflow and a Thermal R&D axel back and having a friend set it up for me. but i'm wondering if i will need to put a resonator or buy a new one. how much do you guys think the price difference will be? thanks.