How does those car's weight compare with the SE? I've had more front wheel drive rear bearings fail than front, more front bearings fail on rear wheel drive cars. But is a small data set.
Yes Pirelli tires tend to be expensive, but it varies by size. The next size larger is $60 less money each... and based on previous experience I would never use wheel spacers to fit tires. I would use a wheel with more/less offset.
There are more low rolling resistant options in the 16 inch size.
I live in New England, -10 to 110 F, feet of snow, ice, sand, hurricanes, inches of water, twisty roads, high speed highways, a couple friends at the end of long dirt roads. The A/S tire suits our SE use well, I have other cars/trucks for weather extremes.
By the way, the mini uses the same wheel bearings as several BMWs, its a BMW part. The BMW shop down the street routinely replaces them.... but getting off topic for this thread.