i agree with everyone about making it look more dingy but you are really awsome at this I only wish I could do this. will there be any tread on the tires? on the drums I think it would be cool if it had it like they been played on for along time wear and tear.I really enjoy your work alot. i look forward in seeing your final with a stage.
Something that I think really stands out is the combination texture and form of the cymbals. Instead of metal discs, my first impression is that of spun glass, from the color, the reflection of light and the form. I'm not sure how you might adjust it in this case but I just wanted to throw that out there. Looking great though!
Also, I think tread on the tires is a great idea and adding some detail to the drums would go a long way as well. What I mean by detail is placing a red zig-zag or bars (like you have on the head) around the side of the hands. Not necessarily by the fingers but closer to the "wrist".
The idea of making it "dingy' sounds kind of cool, I wouldn't make it look too dingy though. Maybe a little bit more used, it overall looks really brand new. Maybe even think of adding in an HDR map to make it look like it's in a place (maaayybbeee if you want to go that far)http://fc05.deviantart.net/fs40/i/2009/042/b/2/High_Res_HDRI_Map_Pack_1_by_smashmethod.jpg