Thanks for the repsonse everyone. I am going to order another Cyclone and put them side by side in the 16x slots. I think the cyclone cooler is actually the best for a side by side SLI setup since the coolers are open which should allow better airflow.
I will try it with and without a window fan to see what gives the lowest temps. I will also try it with the fan blowing in on the cards and also blowing out. I already have an extra 120mm so I mine as well try it.
I played around overclocking my existing setup this weekend. I got to about 830mhz at stock voltage. Not too bad for stock voltage. I was going to try to increase the voltage but I didn't want to do that with doing some research first.
Anyway, what I noticed while stress testing using Kombuster was that my system temps went up dramatically. I currently have a Sonata II case with one front 120mm and one rear 120mm fan. The rear fan I have on a fan controller. At the lowest setting for the rear fan my system temps hit 46c with my cpu only at 38c (E6600 at 3.2). The Cyclone hit as high as 68c which isn't bad. What I found interesting is that when I turned the rear fan to high, which is fairly loud, my system temps dropped to @40c and the Cyclone dropped to @60c. Needless to say good case airflow helps cool the Cyclone. I imagine the Antec 902 I am using in this build will be much better than the Sonata II in that regard.