Not the slightest thing has changed with any of the light of any of the GSX vehicles since we released the first P3D4 version in June.
Dynamic lights are simply part of the objects models and, the only one that we update, was the Hi-Cargo loader that is now dedicated to the left Main Cargo door. All the rest of the vehicles are bit-by-bit identical to the 2.0 and 2.1 versions, and nothing in the GSX code ever controls the Dynamic Lights.
So, whatever performance loss you are seeing, is NOT related to GSX, at all. It's just a generic impact of DL on your system and your settings.
As discussed here and in many other forums, the performance impact of DL is not just related to the object *casting* a light (the GSX vehicle, which are UNCHANGED), but also on where a light is casted unto. So, the SAME GSX vehicle will affect the fps differently if you are on a default airport, or a detailed add-on airport. The more detailed the scenery is, the more it the fps will drop if there's a DL projected ON it.
It's also possible the SDK (and the kind of materials) used to do the scenery could have an effect on this, but we haven't fully tested it.
And, since GSX vehicles operate close to the airplane, it's not just the scenery complexity that might affect the impact of DL, but the airplane model complexity too (and the SDK used, and the kind of materials used too).
Here's a screenshot of DL from GSX vehicles not impacting fps at all (0 fps loss), using the default A321 on the default P3D4 airport.