I had about 80,000 on a confirmed 270bhp with standard suspension.

It was never an issue.
 
After the revo I had so 260ish bhp, it was obviously noticeable and if you booted it in the dry or wet it went a bit side ways but you learn to moderate the throttle. Getting shot of the P zeros helps as well.
 
this proberbly more to do with a good drivable map rather than the bhp/torque level.

for the first 6 months running 320/320 it would torque steer in third on a dry road... but after a while it settled down.. its happens very rarely now, perhaps road surface plays a part.