The M180 engine of the 230/230S was discontinued and the M108 of the 250S along with the M129 of the 250SE were superseded by the M130 engine of the 280S and 280SE.
The M180 engine of the 230/230S was continued in the W114 230 and 230.6, while the the M108 of the 250S underwent a few changes and was renamed the M114. The M129 of the 250SE were superseded by the M130 engine of the 280S and 280SE.