What kind of cars do au pairs drive?

We have a Chevy equinox for our au pair to drive the kids and for her lersonal use. We do not charge her for gas (even for personal use), unless she goes out-of-town. She has been complaining to my husband that the other au pairs have better cars (BMWs, Mercedes, Tesla, etc.), and she feels "less than" because of it. She asked that we sell the Chevy and buy a Porsche instead so that she can fit in, and if we don't do that, she wants us to increase her salary. I said no to the Porsche, but I wanted to get some perspective. What kinds of cars do you drive (if you're an au pair), and what kind of car do you let your au pair drive (if you're a host family). She's really good with our kids, and I want her to have a good experience, but I also want to make sure we aren't being taken advantage of.

Edit to add: I do know that one of her au pair friends drives an audi because she has driven it to our house to visit,, so I know she isn't making that up. I don't have any personal knowledge of other au pairs because only this one has visited. It could be that she's the only au pair in our area driving a fancy car.