Anyone ever upgraded or know of anyone that bought this system for their headset?

http://www.anr-headsets.com/Html_folder/ANRKits.html

I installed the kit in my DC 13.4 August 2006 and it works great. Battery life with a Duracell 9V was about 3 weeks of flight instructing in Cirrus and Arrows, Energizer about 2 weeks. The noise reduction is very good, however with the Cirrus door open on the ground the ANR couldn't quite keep up, same thing with flying a Skyhawk with the windows open. I wonder if that was due to my earseals. I have the old gel earseals. With windows closed there are no problems, but I will be starting IOE in the Saab 340 soon and won't have to worry about wind buffeting anymore.

I wouldn't buy it from the link you posted, I would just buy direct from http://www.headsetsinc.com/ I also recommend the AMP cable and auto shutoff battery box options.

I upgraded mine about 4 years ago with headsets inc. and am very happy. There are highly recommended.