I am shopping around for a W126, and would appreciate a quick summary of the pros and cons of each of the following models.

560SEL
I know this is the top of the line, but I understand that it is very complicated and there are therefore a lot of things that can go wrong. On the other hand, I love creature comforts, and I think this is the only model with reclining rear seats.

A Canadian dealer is advertising an 1988 560SEL, 143K km, $6K CDN. This seems almost too good to be true.

420SEL
I have read that this is the next best thing to the 560SEL, but somewhat less complicated and somewhat more fuel efficient.

I have noticed that the price difference between the 560SEL and 420SEL is negligible in the local market.

300SEL
I have heard great things about MB 6 cylinder gas engines, but I wonder whether this model is underpowered.

300SDL
I have heard great things about MB diesel engines, but I wonder whether this model is underpowered as well. I have never owned a diesel.

I live in Toronto, so I need an engine that performs well during cold winters, which might rule out the diesel.

I will do most of my driving on the highway, likely at cruising speeds as you can usually sail along at 130 km/h on Canadian highways without police interference.

Gas is back up to $1.00 a liter in Canada, even though we have more oil (in the tar sands) than Saudi Arabia. This is frustrating, but not a major problem for me, as I would likely drive no more than 16K km a year.

I like creature comforts, but that is likely not a major differentiator, as all the models above are very well equipped.

I have an above average theoretical knowledge of engine technology, but don't have a lot of practical maintenance skills. I am a quick study though.

My current car is a 1994 Cadillac Deville Concours, which I purchased about four years ago. It is the most reliable car I have ever driven, but I am looking for a second car with more character.

I don't mind spending up to $3,000 a year on routine and not-so-routine maintenance.

Cheers,
Jason