Actually, I've been finding that most performance mufflers are more geared and cutting down the lower rumble of V8 engines and do little for the higher pitched flat six. I plan on cutting these mufflers off and putting flanges there so I can test several different mufflers so I can get the sound AND performance I like. What will I do with the slighty used mufflers I don't like? Sell them to my drag race buddies, as long as it's loud and flows well they're happy
P.S. Where did you find those?