Well, running an engine when it's sub zero material temperature is not good for the engine, but what are you going to do?

- only thing you could do is put it in a heated garage overnight or wrap he engine in a heat blanket, and lets be honest that's not going to happen is it.
Like I mention, try to keep it off the turbo as much as possible, as that will help the engine cope without the sudden ramp up of speed when the turbo kicks in.