Could not tell, but are you using a 3" down pipe all the way to out the back? Will say that turbos really cut the exhaust sound way down. Am running twin turbos with 3 inch down pipes to the ball/socket connectors and then twin 2 3/4" exhausts with H-pipe to twin turbo mufflers (minimal back pressure). Then twin 2 1/2 mandrel bends over the axle. This setup sounds real good, but not nearly as loud as with the ProCharger. Think you would be disappointed with a stock muffler which increases back pressure.