Mercedes-Benz OM642 question on the 280cdi

[bh13coupe]

Hi Guys

I am a little out of my comfort zone when it comes to modern Merc Diesels, my car being an e320 couipe w124. Anyway, the wife wants a used R-class for driving the family in. they are looking like a bargain second hand at the moment and we will prob look at getting one in the next few months.
My questions is, are there any major differences between the the 280cdi and 320cdi OM642 units other than different engine mapping? Could i purchase a R280 and have the engine mapped to 320 spec? Or are there any other variations to the engine other than software?

Any wisdom appreciated.

thanks

 

[st4]

The injectors differ, the 280cdi are a lesser capacity.