Fusion's off to the races

Ford is expected to announce this week that the Fusion will replace the outgoing Taurus as the visual basis for its next NASCAR Nextel Cup car. NASCAR rules require that its racecars be based on production models, so the Fusion is as likely a choice as the Taurus was.
I'm not huge into NASCAR, so let me wonder out loud why Ford doesn't use the Mustang instead?

Aren?t Mustang owners more likely to be NASCAR fans than potential Fusion owners? Though many racecars in the past have been based on four-door sedans, Chevy currently uses the two-door Monte Carlo. Dodge has also begun using its new Charger, which is rear-wheel drive. A Mustang Nextel Cup car would be a coupe and rear-wheel drive, making it at least the same type of vehicle as its racing counterpart. I get the feeling, however, that NASCAR fans don?t really give a hoot what headlight and grille stickers they apply to the cars, just as long as they can go fast and turn left.