http://www.amazon.com/Enzotech-MOS-C10-Forged-Copper-Heatsinks/dp/B004CL89D8
Boom. These VRM heatsinks, $20, should do the trick. and there should be enough clearance between the PCB and the bracket for these puppies. With a water cooled setup and these Heatsinks, overclocking will be a breeze.
Not entirely necessary, since the VRM is what gets hot, and not so much the VRAM, but if you wanted to, there are heatsinks for those as well, at $7.55.
http://www.amazon.com/Cosmos-Copper-Cooling-Heatsinks-cooler/dp/B00637X42A/ref=pd_bxgy_147_img_z