The bitspower galaxy just screw straight into the rams factory heat sink. In most cases it will NOT void the warranty, but you may want to email the specific manufacturer. Most high end RAM (I.e. Fast RAM, anything past 1600MHz) usually has a heat sink that screws into a fin array. The galaxy waterblock simply screws into the factory heat sink.
the Corsair Dominator and the GSkill RAM would both work with that hearsink.
(Sorry for any spelling or grammar mistakes, on my phone)