...they were all once great cars, when they were new.

Thing about BMW's is, they're usually seen as "sporty" cars (much more so than Mercedes, for instance), so they've often been driven commensurately. What this leads to, at least over here, is that the best ones to go for are the ones around (or just above) the middle of each model range: Don't buy an M3, which may have been used to demonstrate its owners manhood by displaying its top speed (somewhere close to 300 km/h; i.e, ~180 mph); but neither buy a 316, which if its (much poorer, but quite possibly wannabe-M3) owner has attempted to do the same, may have had its tiny little four-pot heart flogged to death. Go with the 323 (though not the very first ones, as they were then the top model of the range) or the 325 or, recently, 328; go with the 528, 530, and 540 (again, not the first ones), and not the 520, 523, the early 535 or the M5.

The above might be assuming European attitudes; with the slow bumbling you Yanks (sorry, Bill, I'm afraid you count as one for the purposes of this discussion) are notorious for calling "driving", this issue may be moot?

[To be continued...]