Dealer is probably quoting you RunFlat snows, BMW Rims, and Pressure Sensors... but still.
17" Bridgestone Blizzak LM-25 RFT Run Flat, OE Vehicle Use
Mounted on 17" Alum. Rims-New, Shipping To Toornto, with Taxes, Duty(Everything) is only $1998.00
Using 17" Dunlop Snows (NO RFT) and new 17" Alum. Rims, is only $1600 (Everything in). I don't run run-flats in the winter.
You don't need the time sensors for the winter. I never run them.