thrust bearing faliure is common.
basicly they just get brittle. not warmed down propery can kill them really quick.
ive seen stock standard ones have the rear turbo fail.
and ive seen ones boosted to 15 lbs with no probs
its a gamble and a prick to change the turbos in the car. the best ive mannages is 4 hrs drive in drive out for turbos on a 32 gtr...