I have a 1999 S320 and it has been the best car I have ever owned better than many new cars I have owned. Buying a 140 requires the owner to know about their car to make good decisions on repairs. There is nothing on the road like a well maintained 140 chassis car except for its big brother the Maybach which is built on the same chassis and is known as the 240.

On the S320 the major issue to be concerned about is the 722.6 transmission. If you buy one the first thing you should do is have the transmission serviced by a good indie mechanic. There was a bit of misinformation spread by a number of MB dealers about the transmission being "sealed for life". I guess its true if you plan on replacing it every 100K at $5K a pop. I was lucky and unlucky with my 722.6. After the flush my transmission stopped shifting requiring me to invest in a new valve body. This was lucky as $600 for a valve body is cheaper than $5k for a transmission. This is not something that you "predict" despite popular belief with a inspection or looking at service records.

Unless you want to part with money quickly don't go to a dealer. I was quoted $1000 just to change the spark plugs on my S320 by Mercedes Benz of South Atlanta. I have a great indie mechanic that does great work at realistic prices. If he says its broken it gets fixed period. I am very proactive with repairs and tend to bring my car in at the slightest perception of a problem. My indie is able to handle my S320 without any problems at all and the mechanic that works on my car has a w140 as a daily driver.

I tend to be a bit anal retentive on my car but this is roughly what I have spent on service and maint since I have owned my car. Keep in mind all I only use original MB or high quality German parts on my car.

Mobil 1 oil changes about $125

Transmission Valve body, Swaybar bushings, Front fluid filled joints, Transmission mounts. Many other Misc things $1900

Mobil1 Oil change, Spark Plugs, Wires Coil a lot of other Misc work $600

New Continental Tires $600

New pads rotors and wheelbearings $1000

There is such a stellar difference in the way the S320 and the 300SD that I own drive that I really don't drive the 300SD that often anymore. My car is Black and I live in Atlanta and even on the hottest most humid days the A/C system can freeze me out of the car if set to a low setting. Double paned insulated glass keeps the road noise and maintains the inner tempature of the car. The pneumatically sealing doors with multiple inner and outer seals makes this car seem like a rolling bank vault. The Bose Sound system with quad subwoofers and speakers mounted everywhere including behind the rear view mirror makes a silent car even more silent and is like wearing noise canceling headphones while gliding down the road. I think the S320 is a better value than the S500. The S320 develops 230hp and the S500 is 275hp. The S320 gets better fuel economy and the engine costs less to maintain. All the "classic" older MB's were originally inline 6's and the V8 thing is really just to appeal to the American market.

If you buy buy the latest model one you can find. 1999 was the last year of production for US models only as in Europe the 220 replaced the 140 in 1998. A 1999 model gets you all the final improvements on the 140 without any of the cheapening seen in the 220 chassis. The 1999 models also get you all the "final rev" firmware on all of the computer modules so compatibility with new parts is not difficult if you buy directly from Mercedes Benz. I have heard that the 140 has over 80 RISC processors onboard for many of the computer's that control the basic functions of the car.

The 140 is more expensive to own and operate than its counterparts and is worth every damn penny!! The 140 was a world class car and the 220 and 221 chassis cars pale in comparision in every way. I drove an 07 S550 and right afterwards stepped into my S320 and it was a much better ride and comfort level.