The M123's direct replacement, the 2.6 liter variant of the M103 (starting 1984), was better in every way: that engine not only was cheaper to produce, lighter and much more fuel-efficient, it was running smoother and also had more power and increased revving vivacity compared with the more sedate M123.
More than 30 years after its introduction, the M123 is now regarded as a somewhat classic Mercedes-Benz engine.