DeadGuy, I just got off the phone with Jeremy at DangerDen. He told me that the x48 with brass top will not fit and that the acrylic hold down only has 4 holes not 8 like in your picture. he does no know where the top you got came from, thinking you must have or someone else must have drilled those extra holes in it.
It sounds like my best bet is to buy the MCP universal with a brass top, although it won't cover the entire IHS :( The other option is to buy the x48 brass top and drill my own holes in the acrylic mounting piece, which requires a special acrylic drill bit. Since I need to get this show on the road it looks like I'll settle for the universal MPC.
I'm still not sure what to do with the southbridge. I don't really want to watercool it if it is not necessary since it would add restriction to my loop and make the posibilities of adding a second video card impossible. If someone can verify if the Ek block is low profile enough to clear the video card that would be amazing. For now I think my best bet is the Passive zalaman (this is the one I have on hand)
http://www.svc.com/zm-nb32k.html. I have to admit that its tempting to just order 2 Universal MPC and forget about Crossfire (I have an Nvidia card right now anyways)...
pics? Does it cover the entire heat spreader?