When I talk about DirectX 11, I’m just talking about the API. The DirectX 11 renderer only requires video cards that support shader model 4.0, and uses the downlevel hardware features to support DirectX 10 hardware. So if you have an older card that supports the DirectX 10 feature set, the game still runs using the faster DirectX 11 renderer. You’ll only have to use the older DirectX 9 renderer if your video card supports only shader model 2.0 or 3.0 or you are running Windows XP.
And I think you’ve all convinced me to include the 64 bit exe and dlls.