I don't understand: did you skip the Sports Package because the run-flats that accompany this package are not suitable for snow?
The Sports Package includes active roll stabilization, active steering, and a few other goodies (such as 12-way power seats). Considering that snow in Massachusetts lasts, let's say 5 months per year, I would get the Sports Package and an extra set of snow tires. Each set of tires will last twice as long, hence you will incur no extra cost over the long run. (I have owned two 5-series back-to-back; in both cases the tires wore out after 3 1/2 years.) I intend to drive my 545i on some pretty twisty roads here in northern California, so roll stabilization is a big deal for me.