a straight thru would gain some over a "regular" type with a center nipple and an offset nipple. Not sure how much. I ain't an ex engineer but If I was serious & wanting to experiment, what I'd do to start is take a pressure reading in front and in the rear of the current muffs at WOT. Just WAG I think you'd notice the noise increase but not a performance increase. My pref is a restricted (quiet) system with open cutouts right at the collectors. with the money in a third parties' hand I open em up & 10 seconds later its all over but the cryin & the money is (now) in my hands then I close the cutouts