1) The tire wear is not having much effect on grip.
2) You mention that your rear tires have too much grip - WRONG - Your fronts don't have enough. Never, never wish for less grip anywhere. Wish for more balance
3) Judging by the wear, the large differential in hot pressures, and your admittedly limited experience autoxing, I humbly suggest that the problem is not entirely with the car. Please try to drive slower into corners. Most novices complain about understeer when the problem is overdriving.
4) Get an experienced driver to ride with you. He can determmine if you are driving too hard.
5) Get an experienced driver to drive your car (like the guy in the other BMW) He will be able to tell you if the car is a pushing pig or not.

Good luck - Alan