So this question gets asked everytime the temp drops below freezing, in every forum. And there seems to be 30 diffrent answers every time it's asked.

What should you do to warm up the car? There's been all kinds of suggestions, that range from let it idle for 20mins to start it up and drive like hell till it warms up.

The most reasononable and consistant responce from people that (seem to) know what they are talking about seems to be to let it idle for 5 mins and then keep it under, say, 3k rpm's till it heats up but don't let it idle for more than 5 mins.

So what's the quickest most efficent way to start up the car that is the best for the engine?