Hello 
I imported a Pioneer 8200NEX from the states, and i love the machine !
I was just thinking if the raspberry pi can be used with the Pioneer machine, and use the existing touch-screen via HDMI ?
Is that even possible? if it is, it would be awesome to have a small computer in the car 
Yes, I'm using a raspberry pi on my 4200nex to play movies. But I don't know how you would get the touchscreen to interface with the pi.
I just use an RF remote ( https://osmc.tv/store/product/osmc-remote-control/ ), the remote works perfectly and has lasted the test of 3 summers and winters in the car 24/7.
I don't know about the 8200nex, but on my 4200nex the highest resolution I could set the pi to was 576p, which still looks awesome on such a small screen.
What OS are you running on the PIE? Any other uses than movies you've tried?
I dont know my intention yet, but have a full blown computer on board can be wrong 
meybe the touchscreen is not that important, i small wireless keyboard in the glovespace will do it i guess,
dont know if i want a Linux/Windows or meybe emulatorstation för playing games ?
Good to know that ppl have dont it, how did you connect the pi for power? "power" down with the car would have been nice.