xx4 is a FAST car, but has a GLASS front end, stuff a pipe on the sweeper and goodbye arm!....there are mods to beef up the front end on the xx4 but it's still a hassle to keep it on the track, Schumacher medium flex arms are a must have if you are still racing this car....who wants to mess with belt drive when their are much more efficient / intuitive drivetrains available?? I mean a belt drive is not watch building but they are a PITA.....I would go with a Kyosho zx5 FS2 as they are a dream to drive and they are very durable, I hav broken one part after 4 weekends of racing and TONS of practice...........JMO