Bought a 2010 Z4 four years ago with 49K miles on it. One owner. Amazing shape. Had original battery in it! Had BMW dealer go over it. Said it was one of the finest examples of a used Z4 he ever saw. So far, VANOS recall done free, replaced front sway bar links and both front struts. Expensive, but still worth it. Only put about 1600 miles a year on it so expect to keep it for some time.
