I am unsure if the shark fin on our 2018 Subaru Forester is more than just GPS. I’ve been searching but nothing conclusive yet. Of course once you drop the headliner you will know. If I were to get one of the combo NMO/GPS antennas I might go with this one. I remembered that it has a metal mounting and housing, better for the ground plane. I’m not positive if the other one I posted is (though I think it said it was). I did take a look at the area the moon roof retracts to and at least on ours it looks like it comes back pretty far. I know it wouldn’t be in the most ideal position but I might opt for a lip mount that goes on the rear hatch myself. Sometimes good enough is good enough. I’ll definitely follow your progress. Oh here is a video I found on installing the EM Wave.