It's been awhile since Single Dins actually seemed to have good options. I really liked my Alpine Head Unit in my last AP2 with the rear mounted USB routed up the ebrake hole.
What head units do you guys use and bonus points if all buttons (including mute) work!

 

I use a Pioneer digital media receiver (no CD player). It has a super short body depth wise, which allowed me to fit a 90W RMS (CEA2006 rated) mini amp in dash right behind the head unit. Amp occupies stock head unit space that short body hu does not use.

Any digital media receiver and Class D mini amp combo should work.

This way, no extra interior or trunk space taken by amp, and you can reuse stock speaker wiring, since amp out is right next to where speaker wiring starts.

Class D uses so little power, you can power it from spare power outputs on under dash fuse box. No running power cable from battery.

Pioneer now makes a footwell subwoofer, also class D, also can power right from dash fusebox. Can fit under carpet inset in that white foam block at passenger feet. Zero interior or trunk space used up.

Obviously no substitute for a real sub, but to take load off the door mids, use crossover built into head unit, mids can really crank without distortion or annoying buzzing.

Sure, Class D doesnot have the fidelity of serious audiophile equipment, but that would be lost in a noisy, open car anyway. To me this sort of setup is the perfect balance of usable sq and space and cost for this car.