I have the HD oil cooler with thermostat and the LeNale fan. Different equipment for different situations. The oil cooler works best as long as the bike is moving or there is some airflow across the fins. The fan works in situations where you are stopped or moving very slowly for more than a few minutes. Of course, you also need to have full synthetics since they have a higher breakdown temperature.
My 09 Road Glide made the 4,250 miles trip to Sturgis last year in all kinds of weather. I had no worries since I had the oil cooler, the LeNale fan and full synthetics. And boy, it sure does get hot in Nevada and Arizona in August.
If you can't afford all three things at once, I'd replace your fluids with full synthetics first, then put in the oil cooler, and then install the LeNale fan.