I'll be getting my car in early April - so I'll get past this winter without them. At this point - my plan is to get through the summer on the RFT's, get REAL snows for the winter of 2006/2007, then REAL performance tires for summer 2007. A friend who works at a major high-performance tire co also suggests that RFT is a marketing scam - allowing car makers to ditch spares and thereby adding cargo space w/o adding to the car's actual dimensions.
I HIGHLY recommend snows, since no matter what you have to get you going (DSC, DTC, x-drive, active difs etc) it is ONLY the tires that STOP and TURN the car.
The math is very simple to me - it takes simply nudging another car, curb, piece of Armco, to pay for one killer set of winter tires.
I've spent over 300 hours of competitve driving on snow and ice, and can swear by the performance of the state-of-the-art multiceluar winter compounds.