Yeah, was gonna say this.

If you actually do use Lua to significantly alter the actual physics, shit gets fuckywucky really, really fast... its quite inefficient and laggy.

I know, because I've tried to implement custom physics manipulations in Gmod via Lua... the netgraph, and server side lag, becomes absolutely absymal, really fast, if you're trying to use it for more than just a few objects/interactions at a time.

Like the uh... Armored Combat Framework?

That uses Lua to allow you to construct your own custom tanks and what not?

That tries to do things like penetration/ricochet calls on physics and collision hulls... through Lua?

Astoundingly inefficient and laggy in pretty much any situation with more than 3 or 4 vehicles operating and engaging each other at the same time... especially so if they are using high rate of fire autocannons or machine guns.

You have to have an unusually powerful server to be able to handle more than that, and its still gonna chug as you scale up conflict sizes.

As I remember, most ACF servers had/have a bunch of rules about giving warnings before you dupe spawn or dupe save a vehicle design, have maximum part complexity limits, have designated build and designated battle times, or just seperate servers for each... because using Lua to handle so much physics stuff is so often likely to cause server stalls and crashes.