Just my $0.02.

I paid $2500 for an 85 300TD turbo about 4 years ago, 140,000 mi. No sag, but No AC either. Clean interior (minus the cigarette stench). Minor bubbling around wheel wells.

Fast forward four years, still runs like a dream and is completely sound mechanically, but the rust is killing it. It looks like crap, but its structuraly sound. I'll end up dumping it on E-bay when I get my new euro 84 wagon done.

BTW, I paid a little more than 1/2 that for the 84. It is one of the best driving 123s I've ever seen (170,000 miles). Quick smoke free acceleration, nimble, very tight suspension. It was owned by a guy who employed 4 diesel mechanics as part of his family business. I have maintainence records going back to the day it was imported. Very very little visible rust, but oh boy the stuff you can't see. it sags upon sitting overnight, but pumps right up when you start it (needs new springs?). I've put a ton of labor into it and about $150 in new parts, $75 in used parts and $250 for tires (plus the cost of all new fluids). I'll probably come in right around $2500 when all is said and done.