Different compression, slightly different cams + the 100kw doesnt have tvis and is a small port. Ecu tuning would also play a roll in why the 2 motors are so different. Different inlet manifold, different exhaust manifold would also cause the difference you speak of.
But im betting there are more technical reason behind it.
And then you get the odd freak motor, a motor that you can put thru hell day in day out, and still lives to fight another day.
