The trend towards integrating several functions into one component is asserting itself more and more. In this case it's the counter-rotating compensating shafts and the oil pump (on the left), which are mounted under the engine. They are driven by a large gearwheel mounted on the crankshaft. One advantage of the modular construction method is, in this case, that both the larger and more expensive engines and the cheaper one's without compensating shafts, can be offered. If it goes on this way, the customers will soon be able to chose the features of their engines themselves from a component catalog.
By the way, compensating shafts are not only found in four-cylinder engines. They can make sense in practically all engines which show primary and, above all, secondary mass-forces. Thus, it is found in the Mercedes V8 petrol engine, the M156 (from 2006 onwards). Deep down in the V a compensation shaft rotates at crankshaft RPM. It is driven by the double roller chain, which also runs over the camshaft-drive gearwheels, thus rotating in the opposite direction to the crankshaft. 09/08