[Freon]

I think the 135i is a performance car that can get by in winter with real winter tires. I'd go winter/summer swap with a cheap 17" wheels and good winter tires. Especially in Toronto where you'll have plenty of cold weather (<10C or so where summer tires turn into glass and become dangerous) and snow.

Winter/summer is the best of both worlds. It'll cost you a bit to get started and require some space to store the extra set, but I think it's well worth it. Swapping twice a year is no big deal.

That said, PSS is a good summer tire that due to decent treadwear won't break the bank long term. If you did go AS I'd prefer the Bridgestone 970AS. For winter, there are plenty of good options. Blizzak WS70/WS80 are probably the most hardcore snow tire without going studded. Winterforce 3D or LM-22 are good moderate options if most of your driving is still on fairly well plowed roads and maintain a bit more road feel. I have LM-22 RFT and am happy with them. I've owned previous gen WS60 and they were great which is why I recommend the Blizzak WS70/80.