I'm in Raleigh also. Last winter I noticed if I count 15, or so, seconds AFTER the GP light goes off start up was MUCH better. I did use the engine heater on the few times the temp was under 32F the night before. I did kind of cheat though. First thing in the morning - plug the car in, THEN shower, dress, eat. Total preheat time ~1:30 and the heater (cabin) was warm in ~30 seconds.
BTW, folks in Wake Co: I've got mucho chemistry and lab experience but little space where I live. I have made small (under 2 gal.) batches of B100. I'm looking for partner(s) to start making fuel. I do have access to LARGE storage (750 gal) for the waste oil to be processed but it's in Winston Salem. Also, my friend there just sold his old ('83 300D 430K mi.) diesel to upgrade to a newer one. Interested parties, PM me