I continue to have a real problem with oil pressure.  I have tried everything I can think of and, I think, everything that has been suggested here and elsewhere (nopiston, RX7 club, Mazdatrix, web and phone, Racing Beat) to no avail.  My efforts may have increased pressure for a very short while but the pressure has not come up to proper levels (depending on which regulator, stock 2nd gen or the 100lb replacement I installed) nor does it stay higher.  The new pressure regulator, rated at 100lbs, I installed brought the pressure up  to about 70lbs for a very short while but has again dropped to a little over 20 at idle and not getting to 30lbs at 6000 rpm (only at 6000 rpm for a short while to determine if any progress, I do worry, especially about the PSRU-RDb).  Oil is flowing as indicated by the system heating up.