Shoot, anyone who lives in Casper Wyoming drives an AWD, 4WD or FWD in the Winter. Driving an XLR in the snow, mud and muck would be cruel and unusual punishment for both the driver and the car. I have an AWD Escalade and AWD Caddy SRX for all year around driving. The XLR is only used in beautiful weather when I want the top down.
Tell your sister I'm sorry she has to drive around Casper WY under Wyoming winter conditions in an XLR or any other kind of RWD sports car.