as far as I know, 227, is the bhp of the non turbo version. The TT bhp is 325'ish.
No idea
about 6 seconds
Worn suspension bushes, sticking caliper/slidepins on brakes, if it has the 4 wheel steering, get that checked out as very expensive to fix (You can get a kit by TOMs to disable the rear steering, but not cheap either). No idea on common issues with the engine regaring the TT's as wouldn't have a clue on how you would check the turbos.