Oh what a difference an inch can make. (Take that statement as you will.) I made this poll a year ago when my ST was on order, because I was wary about the reviews that talked of how harsh the ride was. Having driven the car for a year now (on the stock 17" wheels), I wouldn't describe the suspension as harsh, but rather taught and tight. This past weekend, I put on my "winter" wheels. Snow tires would have been overkill for me since I don't plan on driving in the snow, but I needed something to handle the colder temps, so I put some Kumho Ecsta PA31 high performance all-seasons on a set of OEM Focus 16" alloys. They're 205/50 16s, so the wheel diameter is half an inch taller, but the sidewall height is a 25% increase, and I noticed a definite change in ride quality. It's considerable smoother and more comfortable, especially as the road quality worsens, and for a car that'll be used primarily for long freeway driving and/or on questionable roads, I'd strongly recommend this as a permanent swap. The downside for me, though, is just how much it numbs the ride. It seems to take away a lot of the raw fun factor and makes the ST feel like more of a "regular" car. I was surprised at how floaty and disconnected it feels now, and I guess I got used to (possibly addicted to?) the feel of the 17s. I appreciate the added comfort, especially with the potholes that the winter will inevitably bring, but I'm already looking forward to the spring when I can put my stock wheels back on. (I also notice a lack of relative cornering confidence, but that may have as much to do with the downgrade in the class of tires as it does with the added sidewall height flex.) For those who have downsized your wheels, either for the winter or permanently, what do you think?