Hi. And welcome to forum. I have built a few carpc's myself. There was this Honda I went COMPLETELY overboard with..
I learned a lot from this build. And I exploited every feature that my carpc build could offer. I got an industry leading(intel) ssd and a quad core processor to make it boot fast, and in its own right it did. But I had the project for 4 years. and for that 4 years it kept evolving and changing and I kept trying to make better. Then I tried something different in my chevy uplander..
This was incredible to me. If you shut the car off watching a movie. when you turn it back on, it resumes. No struggling to get a radio, it is built in and works flawlessly. The big thing for me became to hunt specs for the head unit. sadly the name brands seem to be less than these pure android head units you can get on fleabay. When my Honda project got t-boned and I had to find a replacement project, This is the route I chose..
I just hunted specs on the head unit. The one I got has 1024x600 res. a quad core processor and ddr3 memory. It has a bunch of usb ports and 2 micro sd card slots and it runs android 4.4 kitkat. unlocked by any manufacturer. it does whatever android does. For ~$350. And it installs like a double din stereo. And it is everything we could ever want out of a carpc.
...unless you need to run windows specific software.