X2. I always plug mine in if its below 20 degrees. One night i plugged my rig and the breaker popped and i had no idea. 7 am the next morning and i go to start my truck at 46 below zero, you can only imagine how that sounded. :( couldnt believe she even fired off.
thats true for sure. but they idle like crap and sound terrible for the first minute or so.. i always thought that it was hard on a diesel to do that..