The stock kernel is a slayher I believe, you can use http://www.droidforums.net/forum/cyanogenmod/107143-tut-milestone-oc-application-tut.html if you want to overclock or undervolt it.
i would say stick with the stock kernel, gingerbread is stupid fast at 800mhz. It has some seriously good battery life too. Im getting anywhere from 15-21 hours on one charge. Not to mention the fact that none of these kernels are built for gingerbread. gingerbread runs on 2.6.35.X , these kernels are all 126.96.36.199 which are froyo kernels. The stock kernel has probably been optimized to run with GB but its not a GB kernel.