I had 15" steel wheels on the stock YOKO tires, and they were terrible. The smaller tire (it was 195) made the ground clearance slightly lower, for starters. They were decently quiet on the highway, though.
I made the jump to 16" 205/50/16 Continental DWS and the difference is quite big. In the snow, this car is amazing, though on the highway, at speeds over 70 you can feel the difference slightly (a bit of shaking). Not a big deal, just something to note if you're someone who speeds a bit.
I wouldn't think that the slight weight difference would effect how the car feels and rattles, nor have I experienced any change personally.