There's a Montana FAQ linked on Embeedee's sig.
The rugged mount is the way to go.
Not sure about everyone else but on gpscity.com someone posted pics and a ram mount parts list using the 1.5" balled larger ram parts. I went with this and it seems like the way to go. It's very stable and easy to lock down. Lots of options for mounting depending on your bike and where you want it.
I got the 2013 NT map DVD and Amps mount from gps4us.com since gpscity was out of mounts. Seems there's an issue with the torx locking screw on some mounts and they were recalled, so confirm availability on that.
Honestly I'm not sure you need the garmin maps. The OSM maps are free, routable and seem to be more detailed. I'm a noob but am using these maps so maybe I'm missing why the garmin maps are better.
What I REALLY want are the Mapquest OSM terrain (not topo) maps but I haven't found a download for them yet or if a downloadable version exists.