Winter tires on 18's vs. 19's
I've got an '11 E90 M3 and want to get winter tires & dedicated wheels for this upcoming winter. I'm currently running the 19's that were the optional upgrade when I bought the car (not the wheels that come w/ZCP).
Ideally, I would get new 19's or maybe 20's for the summer tires, and use my existing rims for the winter tires. However, a number of threads I've read suggest traction in the winter will be better w/18's.
Is there that big of a different between winter tires on 18's vs. 19's? I prefer getting new rims for the summer, but not if I'm going to make a big sacrifice on traction in the winter. Thanks in advance for the help!