yes they do work
anytime you increase the pressure of the air coming into the fan ...or desc rease the resistance to airflow coming into the fan ... the volume of air f rom the fan ... and efficiency of the fan ....at any given speed will incre ase ... descreasing temps and improving cooling.
cut out the area under the scoops totally ...to further descrease air resis tance incoming to the system.
you should also remove the thermal control bellows and the air control flap s ...to further improve air flow for hot areas ...
and
add an external oil resevoir and external oil cooler and pump ...and filter ...turning your vw into an oil cooled vehicle as much as air cooled... do all that ... and you can run the sahara at 140f ... yes ...i have done it
good luck