spec 3 - the first 5 gears, vtec activates at 6-6.5K rpm. on the 6th gear, it activates at 6.8-7K rpm.
i can't remember the exact rpm it activates. I'm using my ever forgetful memory to provide this answer.
for spec 2, i think vtec activates at the same rpm for all gears. spec 2 riders please take over