One thing that bugs me about VW manual seats is that the same lever controls tilt and height. Only the mk3 passat had different levers for tilt and height. This made the seat perfectly adjustable. So I added power seats by finding filthy old power seats at a yard, stripping them down, and transferring the foam and upholstery to the power seats. This article shows a mk4 B5 Passat but it really can apply to any car.
Power for the seat motors normally comes from the fusebox but I was lazy and ran power from the rear center console 12V outlet. This is because it's much easier to run the wires from left and right seats to there instead of under the carpet to the fusebox.
Here is the article showing how to add power seats. Also shown is how to reupholster the seats. If you want to keep your new seat skins and foam but just want power seats, you can just transfer them over to a used power seat. There could be some incompatability with wiring if you try to bolt in used seats but if you strip the used seats down there's almost no chance of any incompatibility. In theory you could have power GTI/GLI seats but I don't know if the frames are the same.
http://www.myturbodiesel.com/1000q_how_to/multi/powerseat.htm
Here is another article for center console removal:
http://www.myturbodiesel.com/1000q_how_to/b5/ctrconsole.htm
Here is the finished result: