...if your just looking for parking lot fun, then you really need nothing. Not even the aluminum battery posts, just keep it stock as you won't notice much unless your racing other people. The car is pretty well sorted and is quite fun to drive as is. Any wheelbase is fine for parking lot fun, ...just choose the body you want and set the car wheelbase to suit that.

It's only when your racing that you want to get every second ahead or ounce of potential from the car. ...otherwise you wont' really notice any difference too much.