I'm planning on getting SI's cooling upgrade kit. I think its similar to what Evosport sells for the V8's. I'll need to get it soon before i do more track days this summer. Derek can tell you that last summer's track day temps were engine killers.

http://www.evosport.com/product/vehi.../MBZ_55AMG.pdf

I wonder though if any of the folks with the Renntech Stage I kit experienced any heat soak. Have you Steve H?