Forte SX moving from 17 to 16 wheels

Hello everyone,
Im pretty excited in getting my new forte SX and im wondering if its a better move to go down to the 16's or even the 15's. Just because Im looking at some winter tires (maybe for next year) and theyre pretty expensive for the 17's and the prices drop considerably for 16's and the 15's (about $100 CDN per tire difference from 17's to 15's; just looking at costco)

What are the benefits in these large wheels and tires? Is it worth the size difference? Is bigger better or the smaller ones better? Can I swap the 17's for 15/16's in the winter (obviously new wheels and tires)? Will it interfere with the brakes or the body?

I drive 70% city and 30% highway in Ontario (GTA=Go Leafs!). Even with my current car, Im pretty aggressive and its a midsize with 16's.

Thanks in advance!