Although I never owned a W140 300SD, I did test drive a used one in the late '90s in Memphis, Tenn. w/90K miles on it. I was surprised how doggy it was to accelerate. I drove the car for perhaps 5 miles entering and exiting the Interstate highway system during that test drive. I returned it to the dealer, losing any interest I had in the model because of my opinion that it was way underpowered.

You may be expecting more out of the car than it's capable of in the performance department. Other than acceleration, they're fine cars for the mostpart, sans the rod-bending engines some had.