Hi Lisa,
First, your reply to Mark was really quite rude. If you want help and/or opinions from people, it’s a good idea to not be rude to them.
To answer your question, though, her concern shouldn’t be so much about the car as it is about her guy’s behavior. If she is dating this guy and he’s actively trying to pick up other girls right in front of her, that’s a big sign for her to find a new guy, no matter what he drives. And yes, he probably sees the Benz as a status symbol of some sort (for him to show off), which I’m guessing is why he got it.