A 240D with a stick is definitely your mileage-miser, but it all depends on what you are looking for personally. If you like the ride of a Cadillac, go for a W126 300SD, if you like a big car that can be thrown around like a Mini, then go for the W116 300SD (my personal favorite!). If you prefer a midsize, then the 240 or 300D turbo is right for you. Same goes for the wagon and so on...

As these guys have mentioned, just be wary of shady maintenance records and have the car checked out by a mechanic familiar with these cars. Most expensive things include: climate control, hydraulic suspension (wagons only), vacuum locking system, etc..etc..

I drove my '80 300SD (W116) for the past five years now and it's been a wonderful machine. I have sold it to TXBill who is taking delivery on the 19th of October. I'll surely be sad to see 'Eduardo' leave, but I decided I wanted a W108 280SE for my new daily driver and happened to find one in one of my favorite color combinations (british racing green/tan), and it has zero rust and a rebuilt engine to boot! 280SEs aren't particularly "collectible" per se, so I'm not worried about putting one on the road in the winter.

Well, good luck with your search, I've owned three 240Ds myself and have loved every one of them. One was a stick, and our neighbor bought it from me. The other two were automatics and one is now sitting in TXBill's driveway (the light blue one)!

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Regards,
Aaron