Just out of my curiosity - Is an engine from a top modder (e.g. Murnan) comparable to a factory mill? Our engines don't have many parts that can be modified. It's not like a 4-stroke engine where we have camshafts, valves, heavy conrods and all that stuff. So the is basically not much left to "tune". The timings can be changed and components like piston, crankshaft and conrod can be machined in a way to save mass.
Those things can be changed from the factory or from a top modder. What Do you think?