OK, Tom, I get the picture.
First, consider whether you want a "car" or a classic.
You currently drive a "car", perfectly reliable, safe and comfortable.
A M-B "car", and a pretty good one at that, would be a 300E or E320 from
1987 on. This is a standard four door sedan with a straight six engine,
four speed automatic. Some of these were built with all wheel drive, an
option to have only if one really needs it, IMHO.
I own a '97 E320, it's a nice to drive and a fine freeway cruiser. These
can be bought for as little as $12K and as much as $22K depending on
condition. Always try to buy the newest and best quality M-B that you
can find and afford - for cheap M-Bs are a fool's bargain. The high
repair cost of bringing a beaten car back to a reasonable quality
standard is too high.
All that said, I'm sad to say that a used M-B will have more repairs and
repair cost than a Honda or Toyota. Owning a M-B is an indulgence, like
having a trophy wife - glamorous but expensive.
The second path to consider is to buy a classic. This takes time and
knowledge and one must be an enthusiast to justify the cost. Something
like a a two seat roadster 450SL ('73 to '80), 560SL (mid '80s) are
popular, hold their value relatively well and typically have lower
mileage than their sedan siblings of the same age. These two seaters
have V-8 engines, another version the 380SL (early '80s V-8) is
underpowered, IMHO, for the car's weight.
Old sedans are another area to consider but that subject is simply too
large for this note. Some of these old classics are pretty simple others
are overly complicated and therefore very expensive to have repaired. I
assume by the cars that you now drive, that you, yourself, don't repair
and maintain your cars, if that's true then a classic may not be the
right choice for part of owning an old car is to tinker with it!
I own a '80 300SD, bought new, a larger turbodiesel sedan whose old
technology is all mechanical, relatively simple and can be repaired and
maintained by an owner.
I hope this frames the issue, also see www.mbusa.com and look for prior
models in the site.