PhilZ kernel is 100% stock kernel. He does not make any alterations to it, which is why we don't get any of the fancy features such as undervolting, bln, gestures etc. that we see in Siyah, Dori etc.
This is why there is a different PhilZ kernel for every firmware version, as it is the kernel that came with the firmware itself.
All PhilZ does is adds root+CWM recovery and all his updates are on this and not the kernel itself.