These tops from Daveshouze are manufactured by KEE Auto Tops (
http://www.keeautotop.com/index.html ), prior to buying my top I got a price directly from KEE Auto Tops and the cost was almost $800 + Delivery + Rain Rail + Cables ....... Have no idea how they get the tops for resale on EBay for such a bargain price, and no; they are not factory seconds.
The other option is to pay top price for a two piece top from elsewhere and you will avoid the windblocker issue.
Daveshouze (ebay site) was offline for a while but is up and running again, they answered every question I had, very clearly and promptly.
As for fitting your new top ...... well thats another topic

I did it myself, took around 8 hours.