You have to consider that modern cars are in development several years before release and then the development teams move onto new projects, so revisiting becomes out of the question unless absolutely necessary. So when a company like MMC take on a engine, gearbox and ECU for a 3rd party there is an inherent risk unless they are in at the beginning of its development and have the opportunity to try it in their own end solution.
Adrian
Buggered Off, to a modern none leaky car, heart's still ticking