You're continuing to circulate oil and coolant, which is obviously better than not.

Think of it this way: (acutal numbers made up, btw...) say that oil fries at 300 degrees, and your turbo can get up to 400 when run hard, but since the oil spends a short time in the turbo, it doesn't fry... but after idling, the turbo cools to only 250... then you're not frying anything once the flow stops. (Like I said, numbers made up for the sake of telling the story...) It's better to start the un-oiled cooldown at the lowest temp you can...

It's just a matter of re-aranging your habits: Instead of shutting the car as soon as you come to a stop, do all the "other stuff" first. (unbuckle seatbelt, shut off lights, gather groceries/cellphone/laptop...) Shut off the car as the very last thing you do, usually with your left foot already on the ground on your way out...

-Paul Demeo
1990 780T