Wow- lots of advice here- and most of it is in MB experienced "code". If this guy is new to mercedes diesels- he doesnt know what a 124 is- or a 140. He's thinking 300SD- and in his case he said 300D, but he was wrong- it is a 300SD. (w124/w126/w140 are all chassis designations- several models are on the same chassis, so folks frequently call them by the chassis name.) This chassis on ebay is a w140. It has the 3 liter engine- not the one he is worried about- the 3.5. So the quick answer- the car on ebay should not worry you about the engine in regards to soft piston connecting rods. The w140 is a car that Mercedes intended to complete with Bently/RR. It's repairs are very expensive compared to earlier models, but if they are previously completed, then the car is much better off. Let's give advice specific to this year(s) and chassis. For a first MB- MB/diesel, you might be better off with another chassis/model if you ask me.