Okay well I have a 1999 black honda civic Si. It is basically stock. I just got the car a month ago. My question is.. Is it bad to rev the motor high (like 4-7k rpms), if the motor is not completely warmed up? What damage can it do if any? Sometimes I don't have time to wait so I just go right away. Is it bad to hit Vtec if it's not completely warmed up?

How much time is usually needed when reving high? Sometimes I just let the temperature guage go to right under the halfway point. (which is usually the highest it goes). Is this okay?

Thank you.