ok...a Gsx that is 5 spd, will run 15.1, thats what my talon did stock. but that was with a launch, an auto cant launch like a 5 speed...but your running from a roll-on? i dont know much about supras but 2nd Gen Talons and Eclipses have major turbo problems on stock turbo, past 5 grand they make nothing. at the track i took of 3 tenths of a second by shifting at 6 grand instead of 7 or 7400. try going for a ride and seeing where he shifts, or if he just leaves it in drive. good luck though.