Well Im a new 328 owner myself. Im putting back on my stock 16's with Falkans for the winter. But, Im in NY and the winter isn't as harsh.
As for getting it ready, definately change the antifreeze and also take the opporunity to replace your oil (forgot the recommendation off the top of my head... but check your manual for the correct viscocity for winter driving) You can run a 'heavier' mixture in the summer, but you want a 'lighter' rating for the winter.
Assuming you still have stock rims could also consider grabbing another 2 of em on the cheap and dropping blizzteks for your rear rubber
1996- BMW 328IS
<img src='http://img.photobucket.com/albums/v242/gws226/TEX/neverleanedsig.jpg' border='0' alt='user posted image' />
Performance: Zimmerman Cross Drilled Rotors-- PBR Deluxes-- Cosmos CAI---- Turner Pulley Kit--- Fan Delete mod---
Beauty: 18 polished M-Parallel replicas, Inpro Euros w/ Enchanced Angel eye kit, 20% tint
Clear corners/sidemarkers ---- Eurospec (Depos)
To do list:
UUC System U TDM- 3/05
M50 manifold converstion 3/05
off to the tuning shop for custom software 4/05
Cams/lightened flywheel, throttlebody........ well lets see what happens