Do you have any pics if the work done on the Kohler heads?
Yes, the KR chambers are 'mundane', in appearance,but appearances are often deceiving!
The KR head design breaths well, and with some massaging, I suspect they are as good as anything out there. Look at Navarro heads-he has at least one design based on the KR.
Although, Bob Brooks has a dual plug set, of Aussie designed chambers, that I'm curios to see results from!