13? That's a terrible number!
This is the company that makes Convertible tops for a lot of the higher end cars. you'll probably need to buy or make the bows & hardware for the windshield. Again, it's all about the quality of the guy doing the installation. OSH has the lift a dot fasteners & clips. I think Finishline may have the bows & windsheild parts?
http://www.robbinsautotopco.com/index.php