1980 450 SL...

1980 climate control - all models but 240D - is horribly complicated. Has an under hood "servo", logic board "amplifier" and push button unit.

Be sure the climate control works properly, if not be ready to walk for its complexity and cost to repair causes some owners to try jury rigs which only makes restoration more difficult.

Yes, and take a good look at the servo to make sure it's not leaking coolant, as this is one of the main failure modes. It's under the hood, black plastic on top, about the size of a small mellon, has 4 heater hoses connected to the bottom, about 10 vacuum lines, and two electric cable bundles connected. Begin to see the problem?

If you wind up buying the car, its not all bad. George Murphy at Performance Analysis in TN rebuilds them, replacing the failure prone bottom half with an aluminum one. I think he' selling these for $500 and will then repair it for life for $100.

I'd ask for service records first of all. Also consider taking it to a mechanic thats familiar with these cars for a good check up. That many miles on the transmission would have me concerned.

Steve