With the fuel injection, electronic ignition and modern multigrade oils, there is no reason to warm up a motor any more. In Canada in the winter, when it is -30f we used to warm up our cars for 5 or 10 minutes prior to driving. But it was for creature comfort and to keep things like the stearing wheel and vinal seats from cracking, not to protect the motor. The old automatic transmitions would not engage until the fuid had warmed enough, so we had to warm them up until they would move. (My dad's old IH travel-all used to pull in reverse before it would pull in forward. So we would back out of the driveway, and then could not move forward for another couple of minutes).
Granted, you should not run the motor up to full red line until it is up to operating temperature, but running the motor allways wears the motor. Excessive idling to warm them up wears them as much as driving. As long as the motor will run and the drive trane will work, warm it up on the road. Just take it easy at first.