Mercedes has traditionally offered a low-end S-Class for certain markets where engine capacity taxes are a big consideration for buyers (and where excess power is not really needed).

I'll start with the W116 S-Class (1972-1980) which had the carburated 280S as its entry-level model. This car was designed for the Middle East, Africa and certain Asian markets where the local engineering couldn't yet cope with fuel-injected motors.

On the W126 S-Class (1979-1993), the 280S was again the entry-level model. Same reasons as above.

The W140 had a S280 option. On the W220, the S280 was only offered in RHD. Sorry to make this short but my mom is calling me to dinner!

Continuing this tradition is the W221 S-Class.