Two things that would concern me would be the engine and transmission. The M112 engine is good for many, many more miles if it has been serviced properly with Mobil 1. I may get slammed for this, but if its been changed with dino oil for 170K its probably gonna use a lot of oil - easily a quart every 1K if done by the FSS instead of 5K or less between changes. The other thing is the transmission - if it had its fluid changed with proper MB fluid at least once along the way (preferably by 100K) its probably OK. If its never been changed then you are near the end of the life cycle of the tranny and its not cheap. The car is somewhere probably between a decent car with another 100K service life with some diligent maintenance, to an absolute money pit if worst case.