01-05 YAMAHA RAPTOR660: Big Gun Evo Race Slip-On Exhaust Big power is what you can expect when you install the Big Gun EVO Race series muffler. Stainless steel pipe construction that has been tig welded give the Big Gun Evo Race series exhaust the durability to last. Big Gun sheds the pounds by using a 6061 aluminum sleeve on the Evo Race exhaust. A CNC billet aluminum end tip can be removed from the EVO Race muffler for servicing with a fresh look. The sleek design of the EVO Race muffler provides plenty of clearance for the brake system when the swing arm is compressed.