640d purchase: what to consider, what are your experiences?

After the diesel-bash seems to take off (you probably don’t dare to drive), I tend to go back to the 640d convertible from 2012 onwards. Although the 650i would be nice, purely from the sound alone, it is currently not affordable (from 2013 onwards with the engine-facelift on 448hp). Furthermore, the injector-defect messages, which you can read many times, scare me. How about 640d (which should not be inferior to the 650i from the passage), what should be taken into account when buying (max. Speed 70tkm)? Thank you GGA