ok so it's been a long time since I've been on here, and hello all again. I've had the flowmaster super 40 on my car since mid may and my gas mileage is deplorable. my 380 hp 02 corvette gets better gas mileage than this thing. So I'm thinking of switching mufflers. Can anyone tell me what kind of mileage gains/drops their muffler got them? ldub with borla? anyone with the pv? or even a different flowmaster? I've been reduced to driving my mom's car back and forth from work for the time being. oh and its for sale too if anyone is interested.