Warming up engine...
 

How important is it to let your engine idle to mid temperature, after a cold start?? Does it really make a difference??

I tend to let it idle for half a minute before driving.

You can drive it immediately but keep the RPM's and engine load low.

However, the engine is not warmed up when it hits TDC temperature, <5min. It takes 10 min even in moderate ambient temperature, 70f, to get the oil temps over 150f.