On a stock car or near-stock car, there is no real need to move the VTEC engagment point around. If you have some high lift cams or are tuning an FI setup, then it's beneficial to tune the VTEC engagement point on a dyno. If you're going to get a VTEC controller, and then arbitrarily move your VTEC engagement point and then expect a gain, you'll be sorely disappointed. Basic bolt-ons like an intake, header, and exhaust should not necessitate a change in VTEC engagement.