Thanks for your input Nik, I will closely watch your worklog when it will be started.
I am sorry I have been busy on some family issues and finally able to get back this project. Maybe you already bought your speaker. I just bench tested my amplifier. I don't have very good ears and usually can't tell the difference between different speakers, but at least I would say it doesn't sound too bad. I admit I am using a pair of cheap speakers:
Next step I will have to test it in my car. Let me work on the wiring harness a bit and give an update here.
I had once considered NUC but I thought it needed a 19V DC input. Since I don't want an extra step-down regulator for my 12V lilliput I gave up the idea. And when I figured out I was wrong (NUC is okay with 12V DC, both the internal and external power jack), I made an order without second thought. i3 is so powerful and the idle power consumption (~4W) is just sexy.
I am already started designing a customized enclosure for the combination: Lilliput + D34010WYB + TDA7850 + DCDC-USB. Will probably share the model files so that people can print it with their own 3D printers.
Thanks very much for sharing with us your test result on this amplifier, good luck with your project and I will watch closely this thread to see the final integration of the NUC computer in your car!