Heated seats in a drop top are wonderful. If you can do it yourself, the pads are available on ebay for around £30 per seat.

The electrics should be through a relay but the problem is do you feel happy to strip the seat and put it back together and still look the part

So getting some one to do it that has done it before does make a difference.

Typical kit for one seat.

http://www.ebay.co.uk/itm/Seat-Heater-He...=item5654951305

Get both seats done if you can.

eddie