I also did a test install of my dash-mount mirror from RaceMirrors. I just mounted to the dash with double-sided tape so I can get a feel for it. The original aluminum stem was way too long, and ordering a custom length stem was too expensive. So, I bought a 6mm ID carbon fiber tube and made my own. I can cut the tube to any length I want to get the mirror height just right. After I finalize the stem length, I'll drill into the dash to mount the mirror permanently.
The mirror is really small, but the glass is convex, so you can see quite a lot in it. Being mounted to the dash keeps it completely out of the forward view, so it get in the way like the original mirror. I've been wanting a dash-mounted mirror for quite a while, so I'm hoping the is the solution I've been looking for. I'm planning on getting a new windshield soon because this one has a few rock chips and a lot of scratches. The new windshield won't have the black tombstone where the OEM mirror used to mount.