The Tom Toms are really good as well, they are all rather cheaper now too.
As far as the power issue, now I have done this on a boat from a 24 volt system by buying a invertor and bypassing the regular fuse box by using an inline fuse and hooking up the power invertor that way, it could be installed out of sight to keep it out of mind but still give you some 120v power outlets for your accessories.
