The GSX Manual explains all of this. Ground vehicles are generally of different kinds:
- Living World vehicles: these wanders around the airport randomly, not performing any service. These are always customized by region, regardless if you use GSX or other similar products.
- Airport Service vehicles: these serve AI airplanes OR your own airplane if you use the default ATC Ground Services. When installing GSX, it comes with custom Airport service files for every airport, which means they would get priority over other product that offer these vehicles on a regional basis.
- Proper GSX vehicles: these will serve only your own airplane, only when you use the GSX menu to get a GSX service. Whatever default ground vehicles you had before, will be removed from the selected parking spot when GSX is called.
About Jetways, GSX replaces all jetways at default airports, with individual models in different styles ( steel, corrugated steel, glass ) and hundreds of different operators around the world. However, we haven't replaced the default Asobo model itself which means, if for some reason you would rather have a single jetway model, if you disable individual airports from GSX Jetway replacement ( using the Config panel in the installer ), the jetway there will go back to either the default Asobo model, or to whatever model has replaced it when you use a 3rd party jetway replacement product.
Also, if you have a 3rd party airport that used the default Asobo model, and you used a 3rd party jetway replacement model for it, installing GSX won't affect these airports, since GSX jetway replacement is only meant for default airports, not 3rd party airports ( regardless which model they use )