Nothing more to add to previous posts that hasnt been said. If you take care of your engine, it will take care of you. I never switched off the engine before letting it idle for alteast 10 sec, no matter if I crawled in the traffic or went off straight from motorway. And especially after heavy driving I let it cool for like a minute or so. Turbo still works the same way as always have so by switching the engine you are switching off the oil flow. By this logic you cant hurt the turbo by letting engine idle for a while, but you CAN doing otherwise.
BTW Its said that T5 engines are bulletproof and it will be the last thing working when rest of the car (with FoMoCo parts) gives up
but its only applicable when you take care of it.