has anyone gotten new tires yet? i have an x5 4.8i with 21" wheels. i had a slow leak in one of my tires. i took it to ntb to have it fixed. they had a really hard time getting the run flats off of the rim to repair the tire. and they had a hard time getting it back on again. and they ended up damaging the wheel. it turns out, the run flats have a really tight fit and is very stiff making it extremely difficult to remove. any suggestions on tire maintenance?