I am still running the stock clutch fan setup, but i have NEVER had overheating issues. I have towed a 5000 lb trailer in 95+ degrees in heavy stop an go interstate traffic, and the temp needle has never gone above the normal mark.
now i have the tow package on my truck and i do get a little concerned about tranny temps. if any sort of extra cooling was needed, i would say it would be for some kind of additional tranny cooler.
i would think a good efan setup would also leave you with no problems, and the good thing for you is that you can easly adjust the thermostat on hot days for extra safety.
all in all, i really dont think a radiator upgrade is necessary. just keep your coolant full and verify your efan function, and you should be good to go
