NAVPad Power harness is meant to power just the NAVPad itself. You could upgrade to our deluxe power harness which will power a WX Receiver, GPS, and/or a PDA/XM Music Player
I think I have tried all of the PDA based applications and I also tried WxWorx in an earlier version using a laptop. The one I am using now is NAVAir which so far has performed extremely well. I am reluctant to get into PC based applications because of the altitude issue since I regularly fly at 12000 and above. ATC direct routing is very easy to get when you are at 14000. No one else is there.