For me, the concern about trying to bump an OM602 up to 200hp is less about the work required to tweak the engine, and more about all that effort, plus the need to swap in a more robust transmission. A factory OM603 car can be pushed to 200hp with its stock transmission in place, but I really don't trust the OM602 transmissions to handle that significant increase in torque.

Exactly. The OM602 is a great engine for those more interested in fuel economy, and it would be nice to increase the power output moderately (which shouldn't affect MPG very much)... but any major power boost will stress the rest of the powertrain, which was not designed to handle high torque. The tranny, driveshaft, and flex discs are all much stronger on the 603 models. The rear end is the same though.

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