I just bought a '97S320, Black Pearl Mettalic, Long Wheelbase, 107K, Starmarked from 40K to 100K. Pretty much complete dealer records.

I was not really considering one, until I really started reading about them. I concluded that I would accept the risk of the evaporator, the "Lifetime Sealed Transmission" , and the head gasket issue. I had briefly drive a '95 S500. I don't remember being overwhelmed by that particular car and I didn't like it's massive appearance.

So I was cruising around on AutoTrader and saving various cars about 4 S320's and a bunch of W124's (I've had 3). So up pops this S320 located 20 miles away from me. I had a month long CarFax account and it checked out. Local NE Tennessee car for the last 68,000 miles. Owned in a wealthy little old money town. Car spent 3 years on lease in NJ, then sold under starmark to the guy in TN. I have read that the W-140 is very good in corrosion resistance. Only rust I have found in on the rear muffler.

Went for a test drive. A stack of dealer service records were available for review. It was about a 9 out of 10. To many things to list, but included head gasket, blower regulator, Mass Air Sensor, new windshield.

As far as any quality degradation goes, I sure can't tell. What a ride. Solid, heavy, quiet, and really fast for a 4,500 machine. Totally fast enough for me.
0-60 in under 9 seconds. Great seats, great features, great sound system.
Dual pane side glass really isolates noise, self-dimming mirrors.

So what is the reality of trying to find a good one. CarFax is a must have weed-out tool. Then I think it might be fate. I mean you can find them, but how far can you travel go to test drive them. Seems to me that this is a complex car, but many aspects are not that different from the W124.

The M104 engine is up to 228 HP. It is sitting there in the cleanest engine department design going. There is so much room. Nice plastic horizontal covers adjacent to the insides of the fenders. The hood liner is fastened on rather than glued on. Dual wipers . Re-designed belt tensioner, far more simple. Easier to work on if you are a DIY'er.

The transmission is a snap to service if you have the special $40 dipstick tool.
Replaced front rotors and pads. Nothing special. Easy.

I still have my '92 Sportline with 245K , 90% interstate, miles. Meticulously maintained. It's such an interesting back to back comparison.

The 300E is very connected to the road. A great car in pretty much every respect. Makes me drive fast in the curves and feels glued to the highway.
The S320 changes my personality. The suspension kind of moves around. Steering is more boosted. Less feel. However, after you become accustomed to the car, it can really be pushed through the curves. Brakes are wonderful, but not brake pedal is not as immediate. More pedal travel. Feeling in the S is less rushed, serene, quiet. S is for highway cruising in style. S really settles in at 80 - 110 mph. You can tell that's where it wants to be. Fortunately it's also really good at 75 - 80, which is normal.

The climate control system makes the 300E look sick. It is really nice, dual zone system. You can over-ride the automatic fan speed with a tap of a button.

The headlights were improved at some point in the model run. My model has projector headlights. They aren't as good as the Euros on my Sportline, but they are really pretty good.

In conclusion, the M104 is a very bulletproof engine. The 722.6 will be fine as long as the fluid and filter is changed on a 30,000 mile or so interval. I have not been able to determine the exact point at which MB switched back to non-disintegrating wire harnesses, but logic says 99, 98, 97 would be the most logical choice.

Now that I have one, I would recommend holding out for a Long Wheel Base model. I didn't know it at the time, but now think it looks better than the short wheel base.

If you can find a good one, you will smile every time you drive it.

Steve