OBDII Ecu's don't respond as well to mods, but that doesn't mean they're completely useless. Main thing is that you can't control ignition timing, and that the fuel maps are constantly adapting to your driving style. Still, there are ways to get control of your OBDII Ecu (VAFC) and still make good power.

if you're interested, you can do an ECU swap to a OBDI ECU, like the p28/p73 which are from integras and civics with vtec. This is usually done so that you can use hondata, which is a fine piggyback system.