I never really liked the look of either tranny knobs up to now. The M6 knob we've been shown looks cool, but I'm not sure I'll like the feel. Of course, I haven't grabbed one, so I don't really know, but I've already conceeded to an aftermarket shifter anyways, and they usually come with knobs, so unless the short-throw in the ZL1 is really that good, I'll probably be swapping anyways.
JMVHO. I'll definately be holding onto the ZL1 shifter, though, and keep it as a momento or something like that