I finally got around to completing my single-DIN to double-DIN conversion and install a new head unit. I chose a Kenwood DDX-9904S.
The conversion was a major pain to do. I planned it such that I could spend a few hours on each of 3 consecutive days. The breaks were helpful. If there's one thing I learned--don't take any short cuts. When you take off screws & bolts, keep them grouped together with a label. I've discovered that some screws that appear to be alike can vary slightly, where one screw can be substituted while another cannot, ending up with confusion. Also, when you take apart the center console, there are many gaps that lead deep into the car where a dropped screw will disappear forever. Cover all the gaps!
The double-DIN cage I bought (from a UK seller) came with 2011 auxiliary buttons & bezel. I like the design a little better than on the 06-08 ones. The Passenger Airbag indicator was way too bright, so I covered the internal solid plastic prism with multiple layers of translucent labels to tone it down a lot (it was so bright, you could nearly read by it). I also bought a 2010 CCM with the nicer lighted knobs and swapped them into the 2007 CCM (
DIY link).
One real nightmare in this project was the "A" pillar. The diagrams aren't very detailed and removal & installation is by no means intuitive. I had to take mine off to thread a microphone through it. Couldn't use the existing microphone as it's embedded in a harness that makes it nearly impossible to separate. I mounted my new microphone at the rear end of the main cabin light module (behind the pseudo-vent, which is much better than the OEM mic position).
The Kenwood has 2 wired USB connectors and also two audio connectors (input/output), so I bought two different USB modules with audio jacks. I put the USB and audio input jack module in the CD changer slot located in the glove box. I put it off to the side so that I can install a USB drive and still have room to fit larger items easily.
The other USB module I installed in the center console, on the driver's side near the seat. I test it and it works well. I can't fit a memory stick there because of the seat, but that's what the glove box one is for. This one is mainly for phone charging. The audio jack will take earbuds or headphones.
I wish it came with a light gray cover, but the seat mostly obstructs view of it.