Same! Got this one loaded up with some tunes:
https://www.amazon.com/gp/product/B01BGTG2A0/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1
As far as winter tires go, tirerack.com does list a couple different option on the 20's. One Michelin set and one Pirelli.
My plan (at least for the first winter) is to just have a tire place replace the summer tires with one of those on the existing rims. Maybe later I'll pick up another set of wheels to make swapping back and forth easier.
I've read that you don't even want to *store* the summer tires that come on the 20's in cold temperatures.
Another thing with winter not all that far off: Elon mentioned that they'll sell official Tesla all-weather floor mats by the time the snow falls. Right now, they only have cargo mats for the Model 3.
i bought a 2nd set of wheels for the winter from tsportline, and i use discount tire or le schwab to swap them out for free. they will also rotate wheels.