Diesels don't need to be replaced every "100,000" kilometers. The fuel system is the part that needs maintenance by 150,000 - 200,000 kilometers.

This is also true of many electronic parts for gasoline engines. The big difference is that diesel fuel system parts for CRDi engines (CRDI, D4D, DiD, TDCi, whatever the heck the manufacturer calls it) tend to cost much more than parts for gasoline cars. The injectors alone can cost over 100k pesos a set.

Hopefully prices will go down in the future.

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Maintenance costs (PMS) for diesels tend to be twice that of gasoline. Thanks to local conditions, manufacturers are wary of allowing you to run 10,000 kilometer intervals, like you can with the better gasoline engines out there. So that's an additional 5,000+ every 10,000 kilometers versus a gasoline engine, and major PMS intervals (those 10,000 - 20,000 peso major checkups) are much closer together, too.

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The upside of diesel? Power. Convenience (go further between fuel-ups). Ease of use.