I use the suction cup mount for my -6 and it works perfectly for me. It's mounted on the passenger side and below the canopy rails. However, because the unit is basically shielded from ground stations by the fuselage, I installed an external antenna from Dan (DeltaPop Aviation) and went from receiving 3-4 ground stations to 8-12 at most times. Well worth the cost and effort.
I have no problem with the GPS aspect of the unit as its visible to the skies.
Delta Pop link
http://www.deltapopaviation.com/Home.html ... Couldn't get the link function to work on my iPad.
You are going to love the Stratus. GREAT situational awareness as far as weather.