I am unaware of any new designs that suggest otherwise. But I do know that on older turbos (this applies to all cars, just especially turbos) it is extremely important to allow the car to idle before shutdown. For the reason if you shut the car right off the turbo is starved of oil and will cause premature failure. I have seen lots of Porsche turbos fail because of this. I have also seen Mercedes and Audi turbos fail too, due to oil starvation. The owner's manual does recommend a cool down for turbos, and all cars after hard driving. It is something I always do and highly recommend others do, it is a very small preventive maintenance step to avoid major repair bills.
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