To solve the wannabe problem, just get him some "official baller sneakers." Problem solved.
But really I think it's okay to hang out with him if you are old friends. If you're worried, I would just let people know the backstory when you are hanging around together. You know, "this is my good friend, we've known each other since 4th grade!" It would serve as an explanation for what you two have in common, and it could put you in a good light despite his doucheyness, as if you see some redeeming qualities in him. This kind of friendship can work in a 'Milo and Otis' sort of way.