There seems to be no shortage of opinions of whether "air scoops" or the like actually inhibit or encourage the cooling of the engine.

I don't have enough technical knowledge to offer what the bottom line is but in my experience they are dawg ugly (especially on a 
split) and _usually_ entail drilling holes into the bus to secure them, which in my book is reason enough to to seriously debate whether 
to install them. FWIW my by _used_ to have scoops on the cooling vents, i removed them and don't appear to be suffering any ill 
affects (other than the 8 or ten little holes in the bus that were drilled on either side to secure the bus)

michael