Tc02c gearbox and diff building top tips?

[Monkeysmate]

I'm about to start rebuilding the gearboxes on our buggies and I would appreciate any top tips before I start.
I have some specific questions...
1. Should I grease the idler shafts?
2. Should I grease the gear teeth?
3. What's the difference between the clear and the black grease? Why black grease on the thrust bearings?
4. What's the benefit of the alloy idlers?
Stupid questions no doubt, but I'd value your advice.
Thank you