For reference:
https://bitcointalk.org/index.php?topic=1795879.0In short, it's difficult to predict if any PCIe "splitter" will work with your hardware, unless someone else has used an identical splitter with your motherboard. You might get use of all the slots physically available, you might get some, or you might get none.
I'd also like to add that the rumor that Nvidia GPUs don't work with any of these devices is largely unfounded. Perhaps there are some units that cause problems with Nvidia GPUs, but I have one that works fine with them.
Buy from a reputable seller with a good return policy.