Just my 2 cents.......I have both an '83 300CD and an '87 300 SDL. They offer two totally different driving experiences. The '83 is solid, responsive, and feels indestructable. The '87 SDL is a real highway cruiser and smooth as silk. I usually alternate vehicles every other day on my drive to work. I still can't decide which one I enjoy more. Only thing I'm sure of is I'm glad I have both.

I understand both the 5 cylinder and 6 cylinder 124's are great cars. To me it is a power vs. mileage debate, and to a lesser extent there is a bit of a price difference. I opted for the 87 300D, I don't rack up miles like I used to, so the fuel savings of the 5cyl was more then offset by what I paid for my 300D. The 300D is no mileage champ, and some say they smoke more then the 5cyl's, but then with the 3.0l 603 I don't spend much time looking in my mirrors if you know what I mean. I love the 124 chassis so far, only slightly less nimble in town then my 190D, yet tons more space, and just an all around impressive car, with plenty of diesel power. I shopped for a while to get a good price, and lucked out on a clean well maintained 87 300D. Even knowing the head might let go, if so I am prepared to put a newer upgraded head on it, as the rest of the car would warrant the investment. So far at 220K, with yearly coolant flushes and/or checks it is fine.

Well I think the older 617 motors are great, and practically indestructible, I think the 124 chassis, and 603 motor are leaps ahead in refinement. They might not be 100% as solid, but with care the should come close IMHO, not to mention that some of this is made up by the younger age of the 124 cars. I don't know how I would feel about owning either a 123 or a 124 if I didn't do my own wrenching, there is a lot of stuff to go wrong on both these cars. My Toyota well boring, hasn't required 1/10 the maintenance, but it is as stripped as they come, and I would expect the engine has 2/3rd the life of the 601/603 engines.

In some ways I think the 300D is best for confirmed Diesel heads that want the power, it is something different to drive these days. If it doesn't have 6 cylinders, and headlight wiper washers, I scoff at it, lol! (Unless it's a 1987 190D 2.5Turbo!!
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2411498785&category=6330&rd=1

Good luck on your hunt, it's half the fun! Mack

The 87 is a great car. The trouble didn't start until the next generation when they bored them out to 3.5 litres.