
I've tried both virtual and dedicated hardware (even a Hometroller from Homeseer!), Windoze just isn't the platform for this type of application. After talking to Bert I've switched the RFXCOM LAN interface to IP. USB drivers have been updated a long time ago. The PMIX35 use the Silicon Labs CP210x driver, so I've updated that one to the latest greatest. I don't want to be scared to do an OS, application or driver update knowing it could reduce my stability

I've measured my Powerline network, and it seems fine. Thats why I don't have any trouble with my Xanura network. If I keep the Xanura and build the KNX/A10 gateway this will introduce an extra component or SPOF if you like, so I'm not sure that will keep things stable.
If could get about €3500 for the Xanura set I have, subtract ~€1200 for the KNX/A10 gateway the switch to powernet EIB more feasible. And I'm not sure how much time I would need to program the gateway... switching the powernet devices would take me about half a day.