I'm not sure if you're referring to the V8 here or the CDI. The E500 is probably quicker from a stop until the CDI's turbocharger spools up at which point the CDI will have more torque, but then as the RPM's climb the CDI will run out of breath and shift to the next gear while the V8 will continue to pull like crazy.

Either one that has great torque. However, I have heard that Kleeman has some kits that will increase the low end torque of the CDI

The CDI's torque already starts peaking at about 1800 RPM and it's higher than the V8's. I've never heard of the kit but without making the turbocharger spool up even earlier I don't know how much can be done to further improve the already superb low-end torque. I wouldn't mess with it if it were my car.

I hear the new BMW diesel will have tremendous torque and dual turbochargers to virtually eliminate turbo lag. Might be worth waiting for.

Hmmm. I've never owned a car that I couldn't find more power that I wanted to pull out of it. That is why I buy used cars. Warranty is up and I can do what I want.

Might be.

I wasn't trying to get you to upgrade... was just stating my mileage as a data point. I doubt I would get 33mpg if I drove your E300 the way I drive. ;)

Just thinking out loud.

Back in 06, IIRC it might have been before ULSD, I hand calculated a best of 33 mpg if I was theoretically cruising at 85.