The Hara/Surikarn Editions do have thicker driveshafts (or is this just an updated part which is also on the original Cyclone now too?) but according to people I have spoken to these also bend quite easily.
You can buy some diff covers to seal the diff, they are made by Jet Racing, but alternatively you could just make your own out of some sticky vinyl.
I haven't had any problems whatsoever with the bearings on the diffs, for me these are excellent, straight out of the box they are extremely free-spinning and mine are still running strongly after 9 months of use.