My 79 Pete has the "desert cooling" Package that included a 10 gallon water tank and nozzles in the fresh air ducting.  The literature claims a denser air charge for mometary power gains.  The tank is pressurized off the air system and it has a spring loaded switch so you had to hold it on.  I took it all off and my dad adapted it to his Dodge/Cummins and he says he gets lower EGT on long grades pulling his 5th wheel and less smoke as well as a smoother idle and quieter motor after a lot of use.  Benefits to a 22r, zero in my book.  It has to do with cooling the air much like the ice boxes that the Honda guys use.