i was looking at the same thing, though those drive cups on the gear diff are short, i think u'd have problems with the drive shafts falling out through suspension travel
http://www.rcmart.com/catalog/rc-trf...3-p-26528.html
looking at those outdrives though, the cups look really long. is there anyone here with a 416 who could compare the out drives from it to the 501x / db01 please?