Unable to find the exact product I want, I'm left with one option. Build it myself. My goal is to build a custom car stereo. I don't mean install a set of components, I mean build the actual head unit from scratch. It's for my Duster and I want to keep the original style radio but with modern hardware. The old ones were about half as wide as the current DIN enclosures, so I highly doubt I can simply transplant the guts from one to the other.
Did some searching and I'm not coming up with a whole lot. So I'm looking for advice on what and where I can get components to build such a thing.
I have simple requirements:
- FM radio (HD radio would be cool but not necessary)
- AUX input (to plug in my phone)
The above is mandatory. The below, while optional, is very much desired.
- USB; to charge phone (don't need ipod controls) and media playback from a usb stick
- SD card for media playback
- Small led screen to display track info and radio text.
I don't need a CD or tape player. (or 8-track)
No clue where I can even get circuits to build this stuff. If I need a centralized chip to control everything I do have an RPi2 and RPi zero I can use. 50w x 4 would be fine as far as amplification and some basic EQ.
Any suggestions?

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