Why don't you kick it off by telling us what you thought of?
Thank you! Btw I found a keycard holder that looks promising. Will share a photo when mine arrives. I mentioned on another thread that I had the 3M crystalline tint. That was a total game changer. If you don't already have it, I highly recommend. Exterior wise, I had a full 3M wrap color change and chrome delete.
I think he is looking for things you might want to be improved, but yet does not exist also.
Yes, and knowing what already exists helps to determine what's still needed.
Check out rammounts.com and look through components to build your own. Make sure everything is on the same size ball. I'd recommend 1" for a phone. I've made some pretty badass custom phone mounts to hold my phone in front of the A pillar in other cars. They have really good suction cups and plenty of random sized bases with different screw hole patterns and even many different styles and sizes of clamps. Probably the best way to mount to the back of the M3 screen would be the with one of the medium-largish bases with a flat bottom that you can use double sided tape with. If you want to mount to the windshield, there's a double suction cup base in there somewhere that I'd recommend for longer posts to reduce vibration. It's kind of big so it won't work everywhere and you might not like how it looks. But it's the most stable suction cup mount that I've ever found. It wouldn't surprise me if it works on the back of the screen. I shoved it as far down as possible on the left side of the windshield in our G37 and then connected two of the arms together with a double 1" ball to get the phone mount right in front of the A-pillar.
You can flip the metal disc over and it is a plain black face.
