That's the splitter I was talking about. You will still want to support it from behind though. Check out Sport Compact Car's time attack Miata. They use the same splitter and you can see how to support it.
Look at this:
Project Miata Splitter Mount Photo
I still say you will be better off if you just do chassis work instead of aero. And the S2K does need some help in that area, even as brilliant as it is.