In a message dated 6/19/2013 9:09:49 P.M. Eastern Daylight Time,
hhoffman@IP-SOLUTIONS.NET writes:

So, I'm  wondering if anyone with A/C, that has the duct that runs along
the ceiling  from the front to the rear has removed said duct and determined
if air  circulation is better or worse?
Cheers,
Harry

obviously if you remove it there will be no direct forced air to the driver
 and passenger.

wait till a 98 degree day and you'll be sorry you removed it  :)