i'd use it as my excuse to buy new rims. I'll bet if you act all nonchalant about it, she'll actually fear driving your car anymore.
Its like that whole "dissapointed parent" thing that affects teens / guilts them into doing the right thing.
Right about now I'm glad the gf doesn't like driving my car. Too used to driving big boat-like cars so she doesn't like how responsive everything on the bmws are.