Steel gears are from Kyosho. Shame to them that they don't come standard on RR... Alu last only 5 to 6 gastanks with a decent engine.
Be aware that you need other swing shafts and joints to fit the one way !
Universals are great from Kyosho, stay away from 3racing, they used some sort of weird steel which is really crap.
MTX-4 is a good car, but I rank the RR just a little higher, but all depends on track (technical is great for RR), grip and tyres you use.
I think there are only two cars which really give a fight.. the Serpent 710/720 and the Kyosho V-one RRR.. The RR beats them on a short technical track.
Good luck next race !!!