No petroleum engineer here, but a mechanical engineer, 30 years in the engine business, and an ex-Albertan twice (Edmonton and Grande Prairie, on two different assignments).

Mikedd, there are no block heaters (in the traditional sense, ie jacket water immersion heaters) available for BMWs. You can use a silicone pad heater on the oil pan, available from multiple aftermarket sources, if you like. Not common, but helpful if you are parked outside below -40. 5w-30 and 0W-30 flow OK at those temperatures, but it gets worse the colder you go. The engine control unit is pretty good on the modern BMW engines, I never had cold start problems, and was down to -30 or so several times on trips (I didn't own BMWs when I lived in Alberta). While driving away can be hard on componentry, idling to try and warm the engine will have zero impact on transmission or gear temperatures. Since cold running causes faster wear, the goal is to shorten the duration of the warm-up period, by putting reasonable load on the engine and transmission. That means take it easy, light throttle, but drive as soon as the idle has stabilized (and you have visibility through your frosted up windows).

BMWLOVER: Your procedure is exactly right for the X5. My only comment is that this is exactly the same recommendation for your previous vehicles. The difference is that the BMW is less tolerant of the abuse that your Explorer and Impala put up with.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue