GSX doesn't have any awareness of running over a network so, if it even works, it's only thanks to what those products you are using, like Widetraffic. So, anything out of the ordinary, it's only related how well/bad these utilities work when synchronizing traffic.
The likely issue I see with this, is that utilities made to synchronize traffic over a network, might try to synchronizing standard basic variables used by AI planes, but GSX objects have many custom variables to control its own animations, which I doubt such utility would be aware of.
The issue is, even in the very unlikely case the utility you use would be upgraded to support ALL the GSX custom variables over the network, the performance costs might be an issue, since you would have much more data to transmit and, while AI planes might be optimized, by sending just their last heading/speed and have the AI on the client sort out the position using its own flight model, GSX objects are moved in an entirely custom way, so their exact position AND ALL their custom variables, should be transmitted for EACH FRAME, on the whole network, for each active object.
This would likely result in bad micro-stuttering, which would defy any advantage of using network to begin with, if you had to deal with bad fps and stuttering, you would be better using a single PC with several video cards (which I still believe it's the better option anyway).
