I've had Goldline remanufacture several sets of Porsche calipers over the years, and they did my NSX calipers a couple of years ago. They do a thorough rebuild, and they have an awesome proprietary coating that is super durable. I did many track days with my 911, including a couple of brake overheating episodes, and the coating never changed. Really great vendor and the price is fair, a bargain even.
http://www.goldlinebrakes.com