Can't you keep the stock fan? I've seen people with the Fluidyne radiator and stock fan. The stock one flows more than any electric fan and you don't have to worry about it breaking or shorting out.
I have dual Spal fans and they work fine. I've had Flexalites in the past and those were a headache. I finally got rid of them with the rubber around the frame came off and got caught in the fans. I would go back to stock if I could. Stock fan > Spal > Flexalite