Holy moly, what is that yellow thing on first post
Girlfriend training requires several steps, one is to train her understand that looks are meaningless without function, however this is the most difficult tasks and works only with best examples of girlfriend.
If she still requires muscular looking car, get her VX Civic or similar and add something like this to dashboard, she does not see car when driving so she easily will accept it:
One other alternative is to get her do pocket parking with car she likes to have, if she is typical girlfriend, she will come up with idea of something easier to park would be better.
I'm spending my days with around 20 young female that are different ones each week, I have to teach them technical stuff, that really is giving one bit of idea from average girl and a technical stuff relationship complex, only practical example with them trying will open their eyes, it is useless to even try to talk her out from it, that is at least my experience.