Trying to get the ModularCar from BaseVehicleModule seems im having issues.

I would assume just cast to it.

X as ModularCar

This works.... butdoes not stop damage to the modules.

		object OnEntityTakeDamage(ModularCar Chasse, HitInfo hitinfo)
		{
			if (Chasse == null) return null;
				if (Chasse.GetComponent<rustCar>() != null)
				{
					Puts("i see this ModularCar");
					return false;
				}		
            return null;				
		}​

This is not finding the mono but is finding the modularcar.

		object OnEntityTakeDamage(BaseVehicleModule Chasse, HitInfo hitinfo)
		{
			if (Chasse.Vehicle == null) return null;

				ModularCar car = Chasse.Vehicle as ModularCar;
				if (car != null)
				{
					rustCar carMono = car.GetComponent<rustCar>();
					if (carMono != null)
						Puts("i see this 2");
				}	
			return null;
		}

vehicleModule.Vehicle as ModularCar

I do this in various of my plugins. Vehicle Decay Protection is probably the most relevant here since I'm also blocking damage there.
https://umod.org/plugins/vehicle-decay-protection

Not sure what rustCar is, but guessing it's a custom MonoBehavior. If it's not finding it, guessing it's not on the car?