[Sammus]

Nah the 3s rating is just because of the motor combos are only up to 3s. If you click on the help thing in castle link it even has an option for 12V and says its for 4s lipo - I've even heard (but not tried) that auto lipo cutoff detects 4s OK too. Good idea to stick on a fan and maybe a big cap across the power leads as well to help keep temps down - because its not really officially supported, and although the components are rated high enough, you really are pushing its limits :P