Update: For anyone with a 2017 BRZ Limited who is considering the BeatSonic phone mount, you'll need to do some dremeling to make it fit. The left edge that the phone mount goes around was too tall (far right edge under the wrap in the image above). After trimming it down, the mount works great though.
I popped off the built in mount base and replaced it with a Scosche magic mount:
http://amzn.to/2wCqHCA
Really happy with how it turned out.