can this be split into two parts, input and output and handled by two atmega328's
that should be no problem. the boarduino should have enough I/O pins for the outputs (16 outputs to be exact)
Do I need to have my MEGA turned into an HID device?
nope, the default serial mode works too, although you will have to use a virtual gamepad driver (was using vJoy for a long time)
It just make the whole thing kinda "plug and play"
is there a more direct way of putting this all back behind the screen?
mhm... you can basically put the atmegas right behind the dash board and hook up the pots, buttons and stuff directly.
but if you wan't to use segas ffb board you should go with the original wiring.
what is usually heard from the speakers on the control panel
the original cabinet is basically stereo:
- the dashboard speakers are tweeters
- the speakers next to the monitor are midrange
- the subwoofer... you guess it
can I run two monitors with FFB on both wheels from one PC?
can I run two sets of speakers so that each driver has their own experience on one PC?
you can absolutely do that. I did it with outrunners once.
however note: running a dual screen setup strongly depends on the software used.
the m2emulator cannot be run "fullscreen" on anything but the first screen (sure, there are tools like dxwnd to "fix" that issue).
also the m2emulator will run on the "default" audio device, so you'll have to switch the default device before starting the second emulator.
with outrunner that was pretty straight forward, as outrunners is basically dual mono - mame outputs player 1s stuff on the left channel, and player 2s on the right.
I'd rather use two pcs. (for most likely any racing game out there
which is better btw, mame or Model2?
for daytona I'd stick with m2emu for the time being.
the m2emu has some flaws (like running too fast - 60hz instead of 58hz) but most people won't notice.
the mame driver might mature over time, but currently is kinda unplayable. graphic glitches and a serious speed problem (game is running exactly half the speed it should run at - most likely an irq issue)