yea, the f23 intake manifold tends to have much better flow proporties than the f22 counterparts. i dont quite know where the idea that the a6 manifold is better than the f23 manifold, but i dont think it is. i personally have the manifold from an f22 engine from an EX accord, but i run it, not for the flow dynamics, but because its an obd1 part and has the obd1 iacv which means that i can properly control my idle with my engine management.
as far as doing it, i dont recomend it. unelss theres evidence this a6 manifold flows better, its not worth the work to hhave to install it, convert the iacv plate to work with a 3 wire IAC.
and as far as the myth that the h23 manifold will bolt on, i beleive thats incorrect. the top plenum of the manifold will however bolt to the lower part of a certain model maifold used on the f22 motors, but nothing more, the H and F series heads share no likenesses as far as manifold bolt patterns go.