I ran all season runflats last season without issue (but we also go no snow)
Unless you can sell the stock tires, just use them up before you get snows. Hunt on CL for some tires. There are usually good deals to be had since the tire sizes are common.
328| ZPP | ZSP | ZCW | CA | 6FL | NAV | XENONS | 18x8.5 VB3s ET30/25
2011 Jet Black
535i xdrive | ZPP | ZSP | ZCW | 6FL | NAV | 331s Square