Bob:
I tell you what I'm gonna do for you. You buy that GT2 and no matter where you live, I'll fly out at my expense and bring my sawzall with me. I've got a new metal-cutting blade in it I've been dying to use and we'll cut you a sunroof in the top or take off the whole top... the more cuttin' I get to do the better!
If you have a buddy that has a tig welding machine, he could slap a couple of aluminum cross braced underneath the car to give it some structural rigidity that the roof was providing and bob's your uncle, you just got yourself a GT2 Cabriolet!
PM me with your info so I can book a ticket
PS - If anyone is reading this and Bob actually takes me up on it, your kind donations to my hospital bills would be greatly appreciated. Bob will have big hospital bills to pay too... Lord knows some Porsche lover will find us doing this to the GT2 and kick our butts fourteen different ways until we can't walk or talk or see out of either eye.