I wished they made a better oil cool down method, such as circulating the oil after you shut off the engine for 'x' amount of time...Otherwise to me, those turbo timers are pointless as I still have to sit in the car (not going to leave it in neutral like an idiot) and wait...But, I already have one in the car (came with it), so I do use it; just not something I would waste $$ on.
Suppose they would make more sense in an automatic, so you could put it in park, set the brake and lock the car and just let it shut itself off.
As for letting it cool down a little, I always do but the time varies...if I just got off the freeway for an extended period of time (esp. with hard runs) I'd let it idle for a bit; whereas if just went to the store I'd let it idle for only a few seconds.
My turbo looked pretty much new when I took it apart, so between using high quality synthetics and frequent changes and letting it idle down for a bit (or more) I believe those helped keep it that way...if you ever see what excessive heat does to oil that sits (coking) and how small the passages are, you'd probably want to do the same.
