Nice write up. I've considered doing something similar for my V1, but the thing is like 15 years old. I know they have the update option, but it's soooo out of date that the dif in price between an update on mine and a new one is like $10.....price of the case, I guess.
I'm not sure what year your car is, but did you look into seeing if the remote volume would fit in the little covered "sunglass" tray in front of the cup holders (if you're in a OG\Pre-LCI?). That way you'd be able to shut the lid when not in use and avoid cutting the CF trim. You'd have to source a low profile knob, but I bet that would be easy to do. Just a thought. Maybe not enough depth under the tray, but who knows.
And I've got to get me some of that rubber shit.
Great job.