The P38 is great but needs looking after, ignore any sign of a problem and it will muliply like the plague. Had mine a year and very happy. I changed the airbags when I got it as they were obviously perished, I had a problem with one height sensor which turned out to be water in the connector and the aircon did not work when I got it which was a simple condensor change. Since then it's been trouble free for 10K miles. Very important to get a full service history and if the last owner has only kept a few months ask why. The diesel is economical and quite quick for a big car when chipped.
All the technical info is available if you are handy with a spanner as are the diagnostics for the electronics.
Good luck if you decide to buy.