The biggest advantage TO drive a manual (6MT) 370Z in icy/snowy/rainey conditions that not one person has thought of or shared is the rev match system. It matches both up and down shifts so traction and suspension isn't upset by drivetrain shock during gear changes. This alone (and patience) allowed me to drive after a suprise ice storm some years ago while still on stock summer tires. Smooth steering and rev match saved that day.
Then I upgraded my tires and never looked back to the idea of a winter car. These tires safely got me through Wyoming, Colorado, and the mountain range of New Mexico during a snow storm that was bad enough to shut I-70 down. I never once lost traction! They're great in the rain and have MUCH better dry handling/traction than the stock tires.
General*G-MAX AS-03