OK, another dealer has said that on a 35i, 17" wheels won't fit.
So to sum up, the best winter tire seems to be the "PIRELLI Winter 210 Sottozero Serie II" (recommended by the local consumer reports:
http://************/3k422vt )
Dealers in Montreal charge between $405 and $422/tire, +$200 installation. So between $1820 and $1888.
Tirerack charges: $274/tire=$1096 + $156 shipping + $77 Duty + $30 Brokerage Fee= $1359. If I get it installed at their recommended place: C. J. AUTO 2000 INC, it's $20/tire, +$5/tire run flat fee + $2.50/tire valve=$27.5 x4= $110 installation. Total fee: $1469.
So I could save about $350.