Dave, I am installing an Advanced on the Fisher Celebrity I am building. The owner has used these on a Velocity and a Varieze, with excellent results. My only complaint about it is the length - at 43", it is hard to fit into the structure in anywhere near a vertical position.
VOR and glideslope antennas mount in a horizontal position, Comm antennas as vertical as you can get them. The Advanced does not need a ground plane - they are center loaded.