Copy from another post... i replied to...

Changing the Vtec point on some engines both higher or lower can increase power by a very large factor, if you provide the correct fuel and ignition to support the early or late vtec change, and in the case of K engines cam angle as well.
Typically those if the car is almost fully stock there is no need to change the cross over point, slightly modified cars normally +- 400rpm or so from stock, and heavily modified car’s can vary heaps. This at least stands true for B H F and D engines. With the Honda K engine even stock form lowery the vtec point by 2000 or more RPM gives huge gains….. but once you make the engine breath better with a nice set of headers you increase the point from stock.. at the end of the day it all comes down to your car your modifications and the ability to how you can have your car tuned.

Regards James