LoMo, handling has changed only slightly due more to my change from 17s w/ Sport Package (already sport tuned) to 18s than the increase in tire width. Overall, it feels a bit stiffer and yes I'm more aware of potholes and cautious around speed bumps. However, due to the slight increase in weight, it feels as if though I can't get off the line as fast. What the extra tire width buys is felt in cornering. I feel like spiderman on the side of a building when I take a corner. It's a great feeling sticking to the road!
Also, I could be mistaken but I believe the xi has greater ground clearance than a regular rear wheel drive.