Neat! I would personally like to change the color of my servo parts manually (at some cost, of course!), but the multiple variants would be awesome, too! It would work VERY well with a trading system. Example: I have green parts for my red servo, and my buddy has red parts for his green servo. Perfect trading opportunity 
Good to hear about part trading! That wasn't originally my idea.. it was a friends. After he had mentioned it, I had started thinking about it a bit more. Though one problem I see could be smurfing. Example: Let's say I'm a higher level and have some of the best parts in the game. I create/buy a new account and give my lower account all the awesome super-powerful parts. I would think that the parts would be tied to certain levels or something. I wouldn't want to discourage new players being matched against another similar-ranked player.... with super-powerful parts. I know whenever I get matched against a higher-player on lower ranks in other games, it can get pretty discouraging.
