There is no metal folding roof on that car, it's all cloth. Given the complexicty of the up coming aerodynamic spoiler at the back + the engine + super chargers, there is no room for a folding metal roof. The roof of an SL folded down eats up the majority of the boot space and granted that the 911 has a longer roof, it would need a monsterously large rear end to accomodate a metal cabrio roof.