Old thread but Im just going to comment here and see what happens. ;)
I'm soon to be in the same boat as the original poster of this thread. Im in Chandler, AZ (Phoenix area) and soon to be relocated to Pittsburgh, PA this summer. We have a 2014 IS 250 RWD and will be experiencing a Pittsburgh winter in 2015. Im assuming that a set of snow tires will be needed to get through our 1st winter. Our IS 250 is leased and we will have another year on our lease by the time we hit our 1st winter there in 2015. Its my wifes car and she loves it so Im sure we will be getting a new one even after we turn this one in. An AWD will be next on the list for both of us since we will be leaving the desert of AZ to the cold northeast.