LS VTEC

it does have a slightly better flow rating than the gsr heads but nothing noticable... the gsr's have smaller combustion chambers than the b16 heads which in turn increases compression more than the b16s will...but i personally like the b16 head for intake manifold compatability/swapability.. that answer your qurestion? there really is not much difference other than the combustion chambers and intake manifold ports/mounting.

What I've researched is that you pretty much put a GSR VTEC head onto a LS block. I think it works about the same as a B16A head because both are pretty much VTEC heads. LS/VTEC is usually done to get more high end power using the VTEC technology. It's not as expensive as a whole GSR or ITR swap but it does require a lot of labor and alignment.

so pretty much just get which ever head is cheapest? right

The B16A's PR3 head design flows better than a B18C's P72.