Experience has shown there's a huge difference in performance and durability between XT and XTR rd's.
XTR cassettes are mega $$$ because they use titanium for the bigger cogs and (I think) the cassette body. Ti wears much faster than steel, which is what XT is made of. Save your money.
I've had terrible luck with Race Face outboard BBs. I installed a new set before the '06 SM100, went through ONE shallow creek crossing (see photo) and trashed them. I've yet to find an outboard BB that's "good", but I've had the best luck with Shimano. Going ceramic will yield less spinning resistance, but you'll still have the same problems with them getting gunked up. Unless you're a top racer looking for every little edge you can get, or you have money burning a hole in your pocket and want major bling-bling, save your money.