I decided to bite the bullet and have this installed in my 2000 S500. I'm very pleased! There is a USB plugin that comes out into the storage compartment right in front of the shifter. I have a lightning cable plugged into it and most of the time the phone sits inside the compartment, out of sight. Eveything can be controlled with Siri. The only exception is navigation. It works best if I pull the iphone out and lay it on top of the sliding lid.
I had the installation done at my local A/V shop and they did a great job. I also had them install a reverse camera that works great.
The steering wheel controls still work as they did with the factory setup. The old clock is now just a blank space next the the shifter letters.
It wasn't cheap, but, in my opinion, well work it.
