I'm not sure as compared to the 6.0 cooler. I have to seen or heard of any numbers of PSD owners running an aux cooler with a fan. If you replace the factory cooler with the 6.0 cooler, you wont need one with a fan. I've had one guy tell me he installed the 6.0 cooler and it lowered his towing temps by 100*F. I don't have any personal experience with these options because I have not installed the 6.0 cooler...YET.