Prm has top and bottom fins too, Jetblastgear.com bolt right up and are aluminum, Rath has longer side fins that "protect" the side of radiator, but I think you need to remove the radiator overflow.........
Jetblast has some of the "cooler" (heh heh heh) graphics if you ask me, and I run that set too.........never argue with a Boeing Engineer......
And yeah the fan doesn't come on as much with the fins installed........only pops on after 3-4 back to back comp hill runs up the little 200' tall Oregon dunes.........
Heapster