i would go with a complete set of wheels + tires for the winter... more money that's right, but much easier to switch, not as much risk of damaging your 19"s when changing tires (if the shop is not careful)... + winter tires in 19" might be a b**ch to find... and even though you know the roads around your place, it's easy to slide onto a curb when parking or even drving slowly, and i'm sure you dont want that on your fancy rims !!
other than that, i think you'd wanna go with performance winter tires to keep a decent level of performance on the dry... i have Michelin Pilot Alpin PA3 on my 280hp FWD convertible, they work fairly good...
as far as storage i know that a few local shops here can store them for you, either free or for like $50 per season. not sure about where you live
good luck, dont wait too long
