id say an h22a4 water pump should work because im pretty sure that h23 vtec is an open deck and pretty much the same block as the h22a4.
i have never rebuilt an h23 vtec tho so i cant swear, there is a guy on here named "drift" he has that motor in his 5g lude so he probably has a better idea about it.

as far as putting that motor in the civic, well i think its gonna be really fast, but you will definitely have to fab a few little parts at least, the wiring should be pretty straightforward with a skunk2 harness and some extra wiring etc.

the smarter/cheaper way is to rebuild an h22 and swap that instead. epecially since most h22 available are obd1.

~boom