In general, I'm quite satisfied with Clio2JVC. For most of the time it works just fine, without any issues.

There are some minor problems I'm working on:

1. Initialization failures.
   Occasionally it does not start up correctly. In such cases a reboot is required. It could be done with reset button, but the controller box is hidden behind the radio. It is easier to turn off ignition for a moment. A bit annoying thing.
   I'll try to put initialization procedure in a loop. It will resend all the required packets until it is correctly initialized. Hopefully that will fix it.
2. Auto-volume issues.
   Sometimes I think auto-volume is too strong. It would be great, if I could control its parameters without recompiling the program in Arduino. I'm thinking about some kind of menu. No idea if this is achievable though.
   Another issue is that mute be cancelled by automatic volume change. I already have a fix for that, but it will only work with remote.
3. Odometer.
   I've added a function to measure distance. Unfortunately, there's an error which impacts displaying distances greater or equal to 100 km. I already have a fix.
4. Code cleanup and icons.
   The code is a mess. It works, but its readability leaves much to be desired. I'd like to clean it up, probably also introduce some more classes.
   It could be also nice if I could control Clio's display icons. I've got an idea that I could blink one of these if voltage dropped below some threshold. So far this functionality is not implemented, I need to do some research about it.
5. Wiring diagram.
   There was a mistake in wiring diagram. Chassis and Arduino GND were in switched places on LM2596. I just corrected that.