one thing to consider on a X is the hard to find driveline parts, mileage is not as much of a consern as how it was cared for, regular oil changes and the occaisional coolent change do wonders for saving money on other things, i wouldn't consider a 200k mile 535 bad and wouldn't think twice, a 200k 525 can be a little rough but still a good car, they are not quite as tough as a 535 though