most modern common rail diesels can suffer with injector, pump, dmf and egr problems as well as dpf if fitted and only doing short runs in traffic and as said the 2.2's are more reliable than the 2.0's.

Depending on the millage it is worth taking off the inlet manifold and cleaning it up and the inlet ports in the head and then fit an egr blanking plate on reassembly and don't be afraid to rag the life out of it every once in a while. Every car benefits from a good booting now and then.

the st tdci's are very nice cars and well worth considering.