overdrive - only disables 4th gear which is POINTLESS because that gear is never used for racing (unless you're going over 120mph or so)
pedals - we only have two, brake and gas. if we're auto, why would we touch the brake, and why would we let our feet off the gas?
sportshift - 7500rpms is the shift point for full auto, but with sportshift you can take it all the way to 7800 (if you got good timing). even then, your second gear rpms will land at about 5200, a full grand short of lift.
sorry to enlighten you ... but if what you were saying was true, then no one would say that the auto gts is slow