Some people have added spacers and pushed the wheels outward, others have gone aftermarket (40-45 seem to be common) and pulled them in a bit. There's some wiggle room with both fender and strut/spring clearance, but not a whole lot.
Remember that when you deviate from the recommended, you risk putting more stress on wheel bearings and can impact how the vehicle tracks. Small changes in rim width and offset, however, are usually unnoticeable.
Tirerack.com has a good database on what will fit. Select the Winter Tire & Wheel Package, and see what they offer for wheels (offset and width). If they sell it, you can be pretty sure they've tried it and know it will work.