I have an '06 GXP and it does have tires that were built specially for this car - reportedly to combat the torque steer. It must work because like I said before, the GP is far more civilized compared to the Impala in that regard.
As far as being faster than a TR - even a stock TR - not by my scientifically calibrated but-o-meter. Just my opinion based on owning both - you are welcome to yours. It may be true that they make more power, but using it in the 1/4 or from a stop on the street can be a challenge. They just don't seem to be as quick.
The guys that are running the great times with these cars are turning the T/C off and easing into the throttle to avoid having the computer cut the torque back (to save the transmission.) According to the Pontiac forums, the T/C engages if it senses too quick a torque rise even when turned off. The gearing is super high to a point where they are hitting 100 mph at the end of the 1/4 in SECOND gear. I sure would like to see one of these with some lower gears and a stronger transmission - they would be awesome.