F.I. Tech or Holley sniper. Opinions from users.

I've got a crazy-*** idea to do an individual throttle body setup, eight TBs and eight injectors. Need to find a controller that will handle that. Still early in the concept phase but I think I can adapt the HW from my 2000 BMW M5
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I like your thinking. It isn't, however, that crazy. There are companies out there that make ITB EFI setups for Chevy, Ford, and even G2 and G3 Hemis. The crazy part will be adapting those to either an LA or B/RB engine since the intake runners are close together. Either way, someone with fab skills better than mine can likely get it done.
As far as finding a controller, I'd say any of the more modern controllers will work. Megasquirt has a fueling functions called Alpha-N. I believe it fuels based on engine RPM and throttle position as opposed to manifold vacuum when using speed density control. Thant being said, I see a rubber hose connecting the ITB banks together. That is likely manifold vacuum. I've also seen a modern LS with hoses from under each throttle blade brought to a block and that was the vacuum reference. You should be able to run it on speed density with that vacuum signal. Now, I don't know how stable the vacuum signal will be since there is essentially no plenum volume.
As far as sensors, no reason you can't use standard GM sensors for MAP, and IAT. I'd use the BMW TPS.