DONT get metal pinions. they are terrible, unless ou never plan on changing the gear ratio on your drr. once they are on its a pain in the butt to get off, unless you have a pinion puller. plus they weigh more
get some mini 4wd pinions, ive never had one fly off and they clean up like new with rc car motor spray. they come in packs of 5 for 2.50 at ultimate hobbies in orange. they come in sizes ranging from 8-18 t