I have never had problem starting my '15 450i that I bough brand new 4 years ago. been out with it as cold as -5°f mine stays outside, or carport to keep snow off
I have however had problems starting my Suzuki V-strom, not when I park it outside, rather when I park it in my basement 55°-60°f . IMHO it is the rather primitive FI, I roll it outside before I start it, but not immediately, first I roll it outside (shovel any snow or sanding if necessary) and put my gear on after cause I don't want to work up a sweat with my gear on. Anyway, I don't really have a problem starting it, rather an issue keeping it running, I have to babysit the throttle till it's warm. I believe the bike's water temp sensor is telling the ECU the bike is warm enuf to run without an enrichend mixture, cause the water temp from being inside is 40°-50° warmer than the ambient air temp