Here's how I did mine. I got the pigtail adapter (at the time from Ramchargers) that directly adapted the dual fan to the stock fan connector. When I did this, the ground wire was overloaded and got hot. So I altered the adapter to run the 2 ground wires directly to ground separately and left the 2 power wires alone. All went well with that and I didn't have to alter the factory wiring/connector.
The reliability of the fan, however, is a different story.