The ram blocks that are out there also seem to be real flow killers. I have that Corsair fan too and it isn't very loud at all. If you are really worried, Enzotech makes some aftermarket heatsinks for the ram if you get a set that doesn't have the big heatsinks already.

HK 3.0 LT is a great block and isn't too pricey. The EK Supreme LT is also a great block and is a little cheaper that the HK and GTZ. The HK and EK don't include a backplate, so I would suggest getting one too. The GTZ does include everything you need and is the most direct to install.