The RM comes with all parts except the washer on the front of t-bar. Just use 2 normal gold thin washers. the o-ring is a normal black one that Tamiya puts in all kits!
I don't remember what oil i had in damper first time i built it, it's a old Low friction Formula damper and not the new one with adjustment. I rebuilt it first with 60wt oil, then after all my problems i used Tamiya's kit oil. They send with oil that is 20wt.
The F310B body is extremly strong, mine has taken quite a beating! Ordered new front wing now, can't find rear wing so i use Tech type B wing at the moment.
I used 1000 paper on diff rings and plain crap Tamiya diff tube.