DDC-1+ with plexi top is quieter than the D5, and a better pump. Take it. DDC-Ultra, is the name they sell the Plus with Plexi-top in europe.

*shrug* Storm is premium. I'd take the "AquaXtreme MP-05 PRO Limited Edition CPU Water Block (delrin)" from extremeprometeia.com, it costs like 25% less than a storm here in the EU/UK - 39£ vs. 55£.