Wait 15 seconds for oil pressure to stabilize, and go. Any longer trying to warm it up at idle is bad for the engine. Best is just to drive it moderately until the oil is warm (not the coolant).

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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