The one from CabrioWorld made by Gahh comes with instructions, the one from Convertible Tops online made my Nachos Upholstery, does not come with instructions. Both those places sell their glass window tops on ebay. The Gahh one has been out longer, the Nachos one came out last month.
Here are a couple of threads to check out, the second one has some good tips for it you do the install yourself:
http://986forum.com/forums/showthread.php?t=3604
http://986forum.com/forums/showthread.php?t=2566&page=3&pp=20
There is information in those threads on the wiring of the defroster too.
I am trying to decide whether to buy one or not too. My top is still in good condition, but the plastic window is only in okay condition. If your top is in good condition and the window is toast, you can opt to get just the window replaced with another plastic window for around $400 - maybe less. Complete plastic window tops sell from those places too on ebay, sometimes for as little as $350.
At any rate, if you buy one and want some help, PM me, I'm in San Diego.
Good Luck,
Larez2
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