The other thing you can do to remove some of the slop from the C hub and rear hub is to put a grub screw in the bottom of them,
I went to all the trouble of polishing my hinge pins so they move freely within the arms, this plus the grub screw i get absolutely no play + very free movement. It only takes 2 seconds to do.
So because i wanted to try something different i purchased a yokomo bd7, guess what after a few weeks of racing i have a play in the c hubs, ok not quite as much as unglued associated c hubs, but play non the less.
Some easy mods to make any 6.1/6.2 better for serious racing (im sure Rick has posted these before)
1) the above mod
2) reflex bladders in shocks
3) reflex 3x1.1 pistons
4) drill a small hole in your top shock cap
5) reflex or new associated drive shafts
6) steel spool outdrives
(reflex ones were ok but didnt last long in Mod, yokomo/spec R spool was a little better)
Beth.