Like it was said before it all depends on how you drive. I myself being a very aggressive driver have totaled 3 cars in the first year or two of driving, some of my friends the same with nicer cars. Two of my friends, that drove back then would be close to SUV's now, got into accidents, not from aggressive driving, but from inexperience. That doesn't include the people I know that racked up points on their license from owning a fast car and very immature. Personally, I would never give my kid, whether it was his/her money or my own, a nice quick car like the Celica for the first year or two of driving. That's just me. Anyway to get back a little here in this post. I sometimes after real hard driving let the engine idle for a couple of minutes or turn it off and let the fan cool things down until it shuts off. I know it's more for turbos just gives me piece of mind sometimes.
umm...if you are goin to turn the engine off...u'd better to just pull ur key...it's the same thing...
the thing to cool the engine off after hard driving is to let engine idle for a while, while the oil, cams transmission slow down its working pace and return back to normal tempurature. turning off the engine and letting the fan cooling off the engine will not get you anywhere.
and for the answer, yes i let my car idle for 1-2 min b4 i shut it off after running it hard.
EDIT: what i usually do is that i drive fast at highways, doing 160+ km/h and open throttle all the time...so when i get off high way, i slow down, and drive it softer than i normaly (which is like when warming up the car in the morning through slow driving-under 2000rpm) would.i do it this way to save gas (idleing eats up a lot of gas)