This doesnt use the Local command or a game logic, so when mplaying across the internet, different effects will occur on different clients.
It needs to be server side scripted.
If you want to really create the Ultimate script, then
Create a looping script that only has 1 instance of it running no matter how many vehicles are on the map, and is written in template form.
also
1) It has the option within it of disarming, or arming each vehicle types individual weapons
2) Respawning if damaged (Optionally switched)
3) Respawning if unnocupied (Time limit variable)
4) (For real coolness, you could have it not respawn, if the last driver of the vehicle was within a trigger area of the vehicle, this would allow it to remain in position, if the driver had loaded it with weapons and was usingm it as an ammo crate)
Ie do it for vehicle classes, and have each vehicle named within a list.
So if there was 20 vehicles on the map, and 5 different types of vehicle, there wouldnt be 20 versions of the script running, or even 4 (1 for each version type).
Just 1 almighty script.
I know your script does some of this already, but to become reliable and totally versatile, it needs more work!
Please keep at it