I also do pulls on the highway and it seems to me the car doesn't sound as it should. It may be the exhaust but im not sure. If you could can u get him to go get his car dynoed at 25PSI on 93 octain. which is what I run constantly. I just want to make a comparasin with what his car is pushing with whatever mods he has compared to my car with just intake and ECU @ 16 PSI on 93 pump gas.