I cut my factory exhaust open on both ends, gutted all the insides out, I got a length of 1.75inch exhaust pipe, drilled thousands of holes in it, making it perforated, then I wrapped that pipe in muffler packing and stainless steel wool, then I welded that pipe to the inlet side of the muffler, then slid the shell of the factory exhaust of it, welded up the front of the muffler, made me a removable spark arrestor, welded up the tail pipe and called it a day. Let me say this, with that spark arrestor removed its VERY LOUD!!!!!