Mango, GTFO of here with your "never had cold start issues" in SoCal, even at 30!
I've replaced damn near everything in the engine compartment in my 01 330i and it still gets a bit sluggish when its REALLY cold outside. Not looking forward to these next few days of single-digit lows in the northeast! I just hope for the best, and always make sure to hit the road as soon as possible and get her moving.
Add this one to your list: I have all new coils too! WTF!
Also Sweets, in my observations, if you happen to go out and move your car when it's cold, as in rearrange cars in the driveway/wherever you part, then shut her off without proper warmup, this situation gets worse when you try to start her and it's cold as bawls.