There's tuning programs out there for OBD0. Not all of the OBD0 ECUs are readily able to be chipped though. If you have a non-VTEC setup, a PM6 ECU from an 90-91 Si (I think, I don't exactly remember) is easily chipped, the earlier ones are a little harder and require a daughterboard. If you have a VTEC setup, an OBD0 PR3 or PW0 works well, or a VTEC converted PM6. There really isn't any reason to convert except that there is more aftermarket support for OBD1 stuff.

I'd stay OBD0 unless you have to change for some reason.