All-season tires don't make a lot of sense for your situation. Why not have the very best (dedicated snows and summer performance tires) if you are going to have two sets of tires? Two sets of wheels is also a no-brainer IMO. Buy a used set off of this forum to save a little. As Ben said, it's way easier to swap wheels vs. mounting and dismounting tires on one wheel set. You can then sell the second set of wheels when you get rid of the car. I hope this helps.
'13 SSII M3 Coupe - KW Clubsport 3-way (Eibach Front Spring Conversion), Akrapovic Evolution, ESS Tune, StopTech Trophy, IND Euro Front Bumper and Gloss Black Mirror Covers, TMS Studs/Lugs, BMW Performance Carbon Fiber Spoiler/Interior Trim/Center Console, BMW Edition Grills/Gills, BMWPedals Extended DCT Paddles, Mode Carbon GT4 Splitter, Advan TC3 (18x9.5/10.5), BBS E05 (18x10/11), G-Force Rivals (275/35/18, 295/35/18)