The B16 head does flow better than others, minus the Type-R's because of the hand port job. The thing that makes the GSR head valuable is the quench zones. IIRC, these quench zones allow for the air that flows into the head to be cooler.

Every LS/VTEC and GSR will yield different number based on a number of factors, to many to list. Not every setup will yield the numbers you want off the bat. That's were performance parts and tuning play major role.