Well heatspreaders is a common debate among nerds and geeks alike
Some say they do nothing but trap heat in rather than actually dissipating it which I could see being that it's just a sticker that brings the RAM and heatspreader together so you gotta wonder how well that little 'sticker pad' in the middle can actually draw heat from the RAM.
Apparently from what I've read that RAM doesn't need any heatspreaders and the guy never encountered any heat problems.
Samsung TCCD RAM chips are able to achieve high FSB's with much lower voltage than the previous champion BH-5's, of course I'm talking about the actual black RAM IC's (integrated circuits) that are on the RAM stick.
The article I linked Yan, the guy never had to use heatspreaders and honestly I don't think you should either as long as you have adequate cooling in your case.
Usually it takes like 3.5v on the Dimm before your RAM sticks start heating up, but of course for your own paranoia you could always throw on heatspreaders or even a small fan blowing down on the RAM, up to you.
Either way I think those G.Skill are mighty impressive for a relatively low cost