I don't really like the C hatchback. It's cheap looking, especially the interior. Actually I sat in a C230 Kompressor sedan and it felt pretty cheap too. However driving it might make up for a bit of the cheapness with mechanical soul, and it sure is a pretty car.
Your buddy should at least get a new car if his parents are offering, not some piece of junk that he has to build up. That would be pretty stupid. I would think he was mature and wise if he said to his parents,
"Ya know mom and dad, this here Honda Civic Si is much more reliable than the Mercedes and it's a lot cheaper too. On top of that it gets better gas mileage and will cost less to insure. I appreciate that you want to buy me a Mercedes but if you don't mind I'll take the Honda."
Problem is I don't think that's what he's saying, is he?