RE: stealth diff lube?
I bought the full sized tube of Tamiya ball diff lube - almost ten bucks - but it's the size of a large sample size tube of toothpaste. I rebuilt my TC5FT diffs with it with zero issues.
If the AE diff lube is less expensive and will cover both diffs, and you don't rebuild them much, then go for that.
I bought the Tamiya stuff b/c I have three TCs though, so bulk is also cheaper.