I'm running 18s with stock sports suspension, it is not "really lowered"... but for this first storm in TO I did fine.
Like Dr G said, the most I noticed was the scraping of some "ice rocks" under the car.
The biggest deal for me so far are the spacers, I'm running 225 all around but have 20mm spacers in the back and I can feel all the time the back wheels kinda of "holding" the car back more than usual.
'11 335i Sapphire Black on Chestnut Brown + Premium | Cold Weather | M-Sport
'06 325i Black on Terracota + Sports | Premium | Cold Weather - SOLD
'99 323i Silver on Black + Sports | Cold Weather - SOLD
'97 328i Black on Black - SOLD