My preferred setup is this:

Stock orange gears
Soft tires (or orange soft slicks from KIT racer) in back
hard ribbed tires in front
2.6 motor (haven't used anything other than 2.6 and 2.2 yet)
stock suspension bar
I race on a hardwood desk (in my dorm room)
and I just kinda slalom around stuff, haven't raced people yet