Well, this much I'm aware of;-
1) A314 is a different expansion (trapdoor) designed to give network, hd and I think RTG support. As it is Pi based, porting the code to extend Pistorm functionality.
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2) Emu68 is just the code for 68K emulation. I think main Pihstorm repo has Musashi emulator still bundled, but it's not difficult to compile with either.
3) Compile? Oh yes. It's very much down and dirty with the Pi to get going,
4) Part of the process involves flashing the firmware to the Pistorm adapter to program the CPLD chips. They can be problematic (different versions due to chip shortage, also no guarantee the board was put together right - shorts are not unheard of, although they are often fixable by the end user.
5) More info here;-
https://github.com/captain-amygdala/pistormAnd you will often find THAT is outdated. WIP-CRAP for most up to date (AlexH and Beany on Discord doing ever more amazing things).
In short, it's very very DIY and a bit of a slog to setup before you actually slap it into an Amiga and power up.
But, nothing else touches it for price really.