For anyone that tries this route, following random tutorials on VGA PCI Passthrough is a route to sure frustration and time wasting (I tried it ~2 or 3 years ago, whenever I built my previous PC). You have to make sure your video card, motherboard chipset, audio, and anything else you want to pass through are all supported. It's much simpler if you can just follow a list that says "this combination of hardware + software works perfectly."
All I did was check the Wikipedia page [1] for IOMMU-supporting hardware, and I needed to upgrade my CPU from a Phenom to FX. You don't need special audio, just the right motherboard (chipset specifically) and CPU. If you do PCI passthrough, it doesn't matter if the Linux host can talk to the card, the guest OS will take care of everything.
Otherwise, check the forums. This has been done many times over the years, and there's no shortage of existing information.