I too found spinning the wheels under power hard to do in a straight line. I now have approx 460bhp and still have massive grip and drive even when it's cold and wet.
There was a chap on m3cutters who is on his 2nd M3. First car had terrible issues with traction but 2nd one is very good as expected. Both had the same tyres and pressures.
For folks with traction issues, I reckon either the geometry is amiss, the diff is faulty or some other suspension problem.