I aquired a 300TD-T a couple of months back and it came with a huge thick three ring binder full of stamps and maint. schedules etc. from the time the car was new. After going through it I noticed that the same Mercedes Shop had performed all the Maint. for the last 15 years. So, I called them and inquired about the fact that the car still had the original timing chain and the injectors were in fact also the original ones installed in Germany. The answer was " Sir, if the car isn't loping at an idle and isn't smoking excessively, and your fuel consumption hasn't changed significantly, then you don't need to replace either of these items" Look, I'm NOT stupid. I'm a pretty fair diesel head too! This car has 352K on the odometer and it's still on the original chain and injectors!!! The injectors haven't been pulled and checked for pattern or pressure either! Sir," If your not loping at an idle...." I guess I have a lot to learn/relearn about diesel engines???? I pull my injectors every 60K on the VW per the Bently maunual and test them, wonder if it's really neccessary?