One example:
Problem engines
Some engines use turbocharging to gain additional sea-level horsepower, rather than simply to maintain sea-level performance at altitude. Highly ground-boosted engines like the 325 hp TSIO-520 found in late-model T210s and P210s and many RAM-converted twins have a dismal record of making published TBO, much less going beyond it. The same is true of the 225 hp TSIO-360 in the P337.
http://www.avweb.com/news/maint/182808-1.html