You want the apple because you like apple macs? No, doesn't work for me at all.
You can't say its 'indevidual' to put a company logo on your roof. Come up with your own logo, that would be cool.
Just my opinion, and my opinion is irrelevant. But your girlfriend has given her opinion, and her opinion you should at least respect.
Can you imagine how stupid a Mini would look with the Windows symbol on it? And I don't mean in a way that it would look stupid because Microsoft is uncool, but I mean in a way that putting any corporations symbol on a mini roof would look stupid.
Design your own logo. It'll be great fun, and you'll be indevidual.
You don't want people thinking "that guy must think he's cool, because he has an apple", you want people to think "that guy IS cool, because he's an indevidual"