Toby's Z4 raced STU at the runoffs without a roof... Seriously, it's have to be at one of the slower tracks, where the air drag is compensated by the much lower center of gravity. I remember a topless Z4 winning at Laguna Seca, but that was Grand Am's ST class. After being on my roof, I'm probably going to keep the hard-top. But, there may be someone who thinks it's the ticket.