What I think is most likely: Try a different fuel pressure regulator, injectors might be clogged and need cleaning, solder gone bad on an AFM (check DIY section for guide how to fix a AFM)
Long shot: faulty O2 sensor (unplug them both so ECU runs in open loop permanently), I only say this because it seems the car is running fine in open loop while warming up, and when it goes to closed loop it starves itself of fuel and stops.
Check the SA subforum for a sticky with trusted workshops, if you live in the northern suburbs send me a PM i'll give you the details of my mechanic who specializes in GTRs (r32 in particular)