Mike,
I dont know of any.. for me the fastest K+B I have ever owed was not modified in anyway.. in the end the fit of the piston and good bearings were the key.
I have had K+B piston and liners last MANY years as long as you keep good bearings in it. If the motor spends a bunch of time lean.. then the fit does not matter.. your custom liner wont last long anyway.
Grim