From my close reading of the Factory Service Manual the OBD2 PCM controls the regulator and thus the pump by: (1) Limiting pump running for only first 30 seconds while attempting each start, (2) allowing pump to run only while engine is running, relying on regulator to control pressure, (3) turning off power after a collision......so the PCM link to the regulator in the module is pretty important.
If I have to run a return line I'll keep this design in mind, it looks to be pretty easy to have made up by a skilled workshop. But my current thinking is to gut the module and fit a pump to unibody with a filter before it. The pump would be wired up to present regulator to control its functions and the pressure at the fuel rail, not requiring a return line.
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