the feathering shaft is identical to the mini titan e325. I just measured it with my digital calipers and it is 4mm. the main shaft is also the same as mini titan. the main gears are compatible with trex 450 (150T).
I got this during xheli's xmas sale. there is no slop in the head. its solid. and yes it does have thrust bearings. the head is identical to mini titan e325. so things like dampers and bearings ,etc... is compatible. this bird feels solid. and its got some heft. probably 900grams or more.