Remember the big GMod+ pack in GMod 9?
Well, with it came a feature where you could use thrusters, and click another number, and use those numbers as well!
In the thrusters menu, below all of the current Thrusters settings, you have little buttons ranging from 1 - 10/other.
Each button ‘saved’ your thrusters in the current game (until you disconnected/map changed/etc).
This way, say if you made multiple cars but couldn’t be arsed deleting them and wanted to control one at a time without freezing, you pressed the cars thruster’s numbers and those thrusters where activated.
To those who would have problems:
Once you’ve placed one set of thrusters, click another number that you haven’t used and place more thrusters.
This would be pretty good for fireworks if you needed them unfrozen but only one at a time or something.