IF I plug my truck in it is almost completly quiet, or atleast as quiet as it ever gets. Since I set the TDCO to -1.76 it IS louder now that it gets down to the 40's at night. I always start the truck up and let it idle while I go back inside pour some coffee, get my crap gathered for the day, and what not. This usually takes ~3-5 minutes, I might wait a bit longer if it wasn't plugged in and isn't runnin 1/2 way quiet yet. I always ease into it and try not to rev over 1800-2000 rpm.
On the cool down comment, I let her cool off if it has been running long distances, hauling, or towing while I pick up some trash/ just give the interior a cleaning. I hate cluttered interiors and dusty dashes so this works good for me.