Thanks for all the replies and suggestions.
I am leaning towards the following choices:
1.
Bridgestones Blizzak WS-70.
2, Conti Extreme Winter Contact (Studles Ice+Snow).
3. Hankook W409.
Since my D comes with the Continentals I think that is my first choice.
Internet research shows the Hankook W409 is quite highly regarded and the cheapest of the three.
My local tire shop says that the BMW 3ers in Canada do not come with built-in TPMS senors attached to the rims. But the TPMS works on measuring the diameter of the tire!
He said the way to determine if this is to check the valve on the
tires. If the valve has a solid chrome stem then the sensor is built into the rims. If the valve has a flexible (rubber) stem then I do not need to install the TPMS sensor.
I checked and my tire do indeed have the ruber stems valve.
I wonder if he is correct?