If your car has a trunk. The heater wont do jack for you. I just simply don't
use my system in temperatures less then -10c as recommended by most
manufactures and never had a problem.

Some peeps are in the habit of warming the car up before they set out
onthe road. I usually just turn the volume down before I leave my car at
night. When I get to the car its warm enough for me to turn the volume up
to an acceptable level. I dont lksten to music that loudly though. My
volume on my Alpine CDA-7892 is set between 9-12.
Just to be on the safe side.
Wasnt the O rings that failed around the shuttle columbia fuel boosters
rubber?
I would warm the car up first-
jeff