If you drive hard and turn off the engine without letting the turbo cool down, since the oil is not circulating anymore it may overcook and damage your bearings.
I always let it cool down, if driven hard, then a couple of minutes of idle, is driven gently, just 30 seconds, just to be on the safe side.
On the start I do not move until RPM falls to 1000 or below, then once water is 90 I wait a few more minutes to get oil up to temp.