TDCi motors – which one is the right one?

Hello Together, after a long search for a suitable vehicle I finally arrived at a car where everything seems to be right: inexpensive, great equipment, … Recently I read, however, that there were many problems with the first TDCi engines and that in 2003 new diesel engines were installed. Now to my questions: From which month were the new engines installed? With the Facelift in October 2003? Is there a recommendation for a diesel model? Is there anything else to come from Austria and would import the car. The large selection and the slightly cheaper prices have convinced ultimately that vehicle to buy in Germany. Thank you for your answers, Marco