The FF Dynamics electric fan I tried actually replaced the stock fan with fan clutch and the fan shroud, but it was not strong enough for the thicker Ron Davis aluminum radiator. The "auxilary fan" added to the front of the condenser (not the radiator) actually does help keep the A/C compressor happy in hotter weather. Two totally different things though. Auxilary fan cools condenser (A/C) and main fan with clutch cools radiator.
I got a $90 fan clutch from AutoZone and it is working better then the stock one ever did (hopefully it will last). If we order a new fan clutch from Isuzu we are forced to get a new fan and fan clutch, I believe Merlin quoted me somewhere just above $300 for both because our older design is not avaliable anymore.