I finally have the touchscreen powered up. Still have to install the driver and run the calibration routine, to get it working properly. Now that I know it's power requirements, 8-20V and a minimum of 2 amps, maximum of 6.. I will need to work on finding a power converter that can supply this and the 5V and 2.5A that the Pi needs.
I also have a fair amount of work to do still on the software side. I have to rework a theme for KODI, to be more car friendly. I will also need to write a launcher script to launch TunerStudio from inside Kodi. I will probably also install some emulators and ROMs, so I can play some games while sitting at car meets and events.