Here's the link:
http://www.engadget.com/2007/06/13/microsoft-beefs-up-xbox-360-cooling-freaking-finally/
It doesn't look too impressive to me. It's just an extension for the GPU, so the CPU isn't going to benefit from this add-on very much. And the cooling system is still way too passive. Putting two fans at the intake would have been a better decision. That would benefit the airflow for the whole system, so that it can actually get the heat out, instead of just moving some of the heat into a corner. Having fans in addition to the heatsink add-on would be even better, since they'd be blowing air directly over the CPU and GPU add-on heatsinks.
But still, I don't think overheating is the primary thing causing malfunctions. There's still the X-clamp problem that hasn't been addressed yet. Just take a look at
these results that show the success rate for just replacing the X-clamps. I think that this is what Microsoft should focus on fixing, instead of trying to reduce the core temperature by a few degrees.