Passat Last Generation: Changes & Updates

Hello,

I'm currently looking for a Passat Variant from the current generation (which has been around since 2001?!). It should have the 130hp diesel engine. Are there any significant changes to the bodywork, the engine, or other components starting from a certain production date ? In other words, should you only buy a Passat from a certain year?

Best regards and thank you for your help.
Carsten.