You wont have vtec if you install killers man.
Do you know how vtec works?in regards to the cam lobes?

Learn how vtec works and why,then you will understand the difference with vtec killers.They dont run the hi and low cam lobes,in other words disabling vtec.
You basically end up with a twin cam honda 4 cylinder with big racing camshafts and no vtec.
I'm too lazy to teach you the theories on big cams etc.lol