I have been dying for a kit like this for a long time. In the summer, 80+ degrees, T-Tops off, the wind feels great but my back gets really hot with the leather seats. Here is the answer:

http://www.sportsimportsltd.com/seatvenheats.html

I can't find any install guides, but it claims its a universal kit. here is the companies web page:

http://www.webastoshowroom.com/seatcomfort/index.htm

 

They look like PC cooling fans.

 

Yea, we could probably figure out a way to do it ourselves cheaper, but this has all the wiring and buttons, 12v all ready to go, plus it'll do heated seats in the winter. I'll update if I end up getting it.

 

Well, down here, I wouldn't have a need for heating. But I could buy 6 pc fans for $24 & wire it myself.

EDIT: Most PC fans are already 12 V