6 psi is the way to go if your wanting to bolt it on an go .... But you can go alot higher if your willing to put in some extra cash to replace some internal parts....If your looking for a great bolt on kit I would recomend F-max....They make a complete turbo kit for 88-91 crxs with b16a transplants ........ It has everything you need including an exhaust manifold , intercoller , downpipe with 2 o2 sensors , boost tube , modified compressor housing , intake tube , T3/T04B turbo , 2 10 inch perma cool electric fans , 35mm TiAL wastegate , wastegate dumptube , HKS standard racing bypass valve , K&N bypass valve filter , K&N filter and a turbo oil line.....Hope this helps you out some ....In my honest opinion your alot better off swaping to a b16 instead of the zc.......Good luck
Ty
Lucky13
