hey guys.. getting ready to throw a dual twister 3 inch exhaust on my car just for the performance improvement. i removed my custom fabed single 3 and ran it around the block and i swear , it must be like 40 whp +!!!! so im looking to do a race/track setup where we will just switch out my custom single for 2 3" mufflers with turndowns put right on the dp's.. what do you think of these mufflers?

http://www.flopro.com/Twister.htm

 

that seems like a weird design but i dig it..what are turn downs? are those the exhaust that you have like a switch that opens them up right under the car?