A properly operating stock samurai cooling system should cool a samurai engine in most any environment. But if you want to upgrade, you could put a trackick radiator in...they are a little bigger and I suppose you could run an electric fan too. But the only time an electric fan will help is at slow speeds and low engine RPM, where the engine driven fan isn't pulling much air through the radiator. At faster speeds (highway speeds) an engine driven fan or an electric fan isn't really doing much to pull air through the radiator. A good fan shroud really helps keep the engine cool too....so be sure you have one in place.
In a normal environment an electric fan shoud not come on unless the vehicle is stationary, or has a very low forward speed (for example towing or climbing a hill in low gear) - under all other circumstances the forward motion of the vehicle will usually push sufficient air through the radiator to cool the engine.
The advantage of an electric fan over an engine driven fan is primarily reduced noise, and theoretically, reduced fuel consumption - on an off-road vehicle, there may be additional advantages, especially if the vehicle is forded or driven through water deep enough to reach the blades - if the bottom few inches of the blade enter the water, and engine driven fan will lift and throw the water on to the underside of the hood where it splashes over everything, including plugs, ignition system, etc. possibly stalling the engine.
If the water is deep enough and the engine rpm high enough, the fan blades act like a propeller and flex toward the radiator and if the radiator is close enough, will destroy it - even with a plastic fan - if an electric fan is used, it can be switched off before entering the water
