I've had an aftermarket power cord on my Node 2 for two months now. Adding the cord resulted in a quieter more relaxed sound; tone, detail and resolution all improved. I also had the C7 inlet on the Node 2 replaced (the prongs on the Node 2 are woefully undersized). This enhanced the improvements that the power cord made.
Cullen Cable made the power cord as well as replaced the C7 inlet. Here's a pic of the cord and the C7 plug with the Node 2.
http://https//www.audioasylum.com/forums/pcaudio/messages/16/169658.html
http://http//www.cullencable.com/avius-series/
Cheers,
Scott