First I heard, so looked them up. $1145 for TBI isn't affordable for me. It uses a GM throttle body (TB) and apparently a GM ECU.
For comparison, I got a complete Holley Commander 950 w/ 4 injector TB for $600 off craigslist, which is typical of e-bay used prices. I have heard that Holley's TB is better and they sell just the TB to GM guys to upgrade from the factory Rochester TB. You can get the earlier Holley Pro-jection 2DI for <$200 used on ebay, but runs a bit quirky since no MAP or IAT sensors (my experience).