I'll chime in. I bought an '89 420SEL almost 6 months ago and put nearly 12K on it. Paid a lot more than $600, and probaly way more than the car was worth. I don't regret it a bit. A new job required a 50 mile commute, mostly highway. Very comfortable and roomy ( I'm 6'3). Mines lowered with 17" wheels , rides very good and handles well for such a big beast. Don't expect more than 22mpg, and thats keeping it at 65-70mph. The 4.2 is enough engine for both power and economy. Forget about mods. Jim summed it up; it's a cruiser not a rocket.

For $600, you got little to loose. But I'm assuming here that you can turn your own wrench. If you start paying a shop $50-80 an hour + parts, you'll spend $600 on your first visit. Expect a complete fluid change of ALL fluids. New belts and hoses. Obvisouly a fuel system service, filter, pump. All this and more is just to bring it up to running status. And thats assuming the eninge & tranny are good, and buy that I mean functional. This car is a high-end machine that requires regular maintainence. Timing chain, rails, tensioner, water pump, brakes, power steering, suspension...all this can add up quick if any of these things mentioned have slipped past their usable service life.

Now having said all that, if it were me, I'd pay close attention to the body and interior. If they passed my requirements, then I'd go for it. Heck, you already know it don't run, so you can expect the worst.

Cliff