Dave, when I did mine I merely used the existing supply via the fuel filter (which I moved to a convenient location on the rear firewall) through two fuel rails, then a pressure regulator (set to ~45psi IIRC) and then back to the existing return line. So my system still had the superfluous fuel accumulator in place, but it didn't matter.
Concept is easy as I know you know.... listen to several sensors:
- manifold vacuum
- incoming air temp
- engine temp
- throttle position
- wide band O2
- RPM
Use tables within the tuning software to determine the necessary fueling duration (pulsewidth) of the injectors for each intersect of RPM and engine load (vacuum) to achieve desired air to fuel ratio (anywhere from ~ 12 to 16 depending on desired power or efficiency, with 14.7 being stoiceometric). Nuances are obviously for enhancing fueling for startup, warmup and acceleration enhancement (transitions on hard acceleration).
The software has auto tuning capability that listens to the O2 sensor and adjusts the pulse widths accordingly.
It's a great system to tinker with and results in a really drive-able car.