Be sure that the Exsys (or VirtuaVia) box is one of the later models, and it is best to use the version that comes without a case/power supply (ie just buy the board set). You can then use a spare case and PSU to build your own chassis. If you use the older model Exsys units, supplied with a case & PSU, you may have to modify your unit in order to provide sufficient power to supply your PCI cards correctly. Until I modded mine, I had issues updating firmware etc... Please see the following link for the full details about the voltage supply issue and the required modifications (you may have to register at the UAD site, to download the relevant PDF instructions).
http://uadforum.com/showthread.php?5259 … -UAD-cards
I contacted Exsys (and their German re-seller), but they refused to take responsibility for the power issues and I simply got mine modded locally in order to get mine working correctly. I believe the board-set came about due to the numerous complaints from UAD PCI card users (in addition to users of PCI cards from other brands).
Otherwise you can purchase a much more expensive Magma PCIe to PCI expansion box. I also use these units, and they work perfectly right out of the box (for all RME cards, including the PCI Madi cards).
Hope this helps,
Kind regards,
George