This setup works pretty well. Plenty of clearence on all the blocks for expantion cards. I use a dual loop: the 1/4" pictured and a 3/8" loop for the cpus. Full gallery is
here.
In retrospect I think I would have preferred to use a single 120mm fan blowing laterally over the chipsets toward the expansion slots. It's a much cheaper and problaby nearly as effective solution. The chipsets do get extremly hot if not actively cooled.