I picked up an 02 DRZ400s recently and finally have it road worthy. The PO did the 3X3 mod, rejetted it, and put on a white brothers exhaust. The exhaust is extremely loud. I am not too worried about it for the street but my goal is to do some trail riding with it and for that I would like it to be quieter and I am pretty sure I need a spark arrestor in some places. Would it be a bad idea to go back to the stock exhaust? Would I have to rejet? If so, what exhaust and spark arrestor could I put on there and keep the jetting?