VTEC controller will simply change the point that VTEC engages, that's it. VTEC is not nitrous spraying or a turbo making boost, simply a different set of cam lobes with more lift and duration. These cams were built to change over at a certain rpm point by enginners who know a lot more about cam design then we do and this changeover needs to be matched with an increase in fuel to keep from running lean. You really won't see a benefit to changing the VTEC point without first changing the cam to one that requires a different engagement rpm and using a dyno and wideband O2 to compensate for the fuel needs of the new cam.

I can hear the VTEC kick on and off on my '98 EX this weekend driving up through the mountains where you need to downshift a 1.6L into 3rd once in a while to get power to climb. I have an intake and exhaust so maybe that's why it's more noticeable.