I raced my friends wrx 07 when he had intake, tbe exhaust, boost turned up to 18+, off the shelf cobb tune, and top mount upgrade. From a stop not so good. From a roll at 40, even for a while, then I pulled slightly. About a car..
We raced 3 times with the same outcome.
He's a good driver and didn't miss gears. I'm pretty good too and didn't miss gears either.
The stock turbos on those are tiny to say the least. His boost fell to ten at 4500. We then changed his turbo to an sti's, turned up his boost to 20+ and it fell to 18 at 5000, put on an ext. waste gate w/ o2 dump(sounds crazy), vic delete and some intake manifold porting.
Then he rapped me by about.... well, a lot! And his car weighs less then mine by about 500 lbs.