Well, for starters I don't know what I'm doing wrong (or right). I have only ever run the stock Flux composite bulk and stock bulletproof diffs without any bearing or gear breakages. I've always run heavy silicon fluid in them (50K-100K) and haven't used any really heavy wheels or larger\longer can motors than stock, so that might have something to do with it.
Diff Case - I have a Vorza center diff and the case is a composite but felt very stiff. If these cases work it would be great as it also avoids loctite\silicon fluid in thread issues.
An alternative to a different case might be to just use a high quality ceramic bearing for the 10x16x5.
Spider Gears - again have never damaged one but would be nice to have a stronger option. Haven't heard of any other options.
Diff Case Screws - Hex heads are heaps better than stock. Have been using some that were in my Tony Screws kit.
Stock screw (M3x15mm)
http://www3.towerhobbies.com/cgi-bin...529+&search=Go
HPI hex screw(M3x15mm)
http://www3.towerhobbies.com/cgi-bin...?&I=LXMAB8&P=7
That said you can still damage the head and it would be great if somehow a larger screw could be used but that's unlikely. With the plastic case I have wondered if I could drill right through the case and put a lock nut on the one end. Probably not enough space in the bulkhead for that though.
What I would really like are harder outdrives. They are what wear on me the most where the dogbone pin rubs.