vcmp server scripts are based on the mIRC scripting language.
I suppose you have not learnt or used the mIRC scripting language (sorry if I am wrong)
Please visit
http://www.mircscripts.org/ for more info on mIRC scripting.
1. announcing every 20 secs: This can be done by using a looping timer. For example, /timer 0 20 /hi would execute the /hi cmd every 20 seconds.
2. Removing minigun, armour from members buying it.
If you are speaking of ammunation. I do not know as I have not tried to do so.
3. Spawning cars.
This is done by setting the cars' locations to where you are.
The alias to use for that certain script for GUS 10 would be vcmp.setvehicleloc