Don, on forced induction, I don't think you will see much ,if any , loss. Years ago ( about 1996?) at U.S. nationals at Indy, Seen John Lingenfelter experiment with headers on his A/D, three different sets, conventional 4 into 1, tri-y, & short dragster zoomies, all runs were between 6.96 & 6.98. Figured the ex. Port was efficient enough on its own that the pipes just didn't make much difference. Probably on a lower RPM car it would have made a bigger difference.