most people think the quicker they get into vtec the more faster they will go. wrong! you should have your car tuned to see where vtec most smoothly transitions from low cam to hi cam. if your car is stock the or has minor bolt ons the stock engagement point should be fine. as stated if vtec comes in too early you will hear it engage but wii have a terrible power drop then will go back up in power. so if stock or with minor bolt ons the factory setting will be fine. if heavily modded have it dyno tuned. stock pr3 ecu has vtec swicth over point at 4800 rpms (obd0 ecu).