From a thread over on Expedition portal:
" A friend of mine is running a OM617A in his G-wagon. The only thing he has done to his engine, besides a total rebuild and an intercooler, is to give the engine some more diesel. This is done by replacing the pistons in the diesel pump, with some slightly oversize ones. Of course, the pump is then timed and adjusted by qualified mechanics. He is taking out a wopping 280 hp!! And this is with the original turbo. It is the next item to be swapped out, for a bigger one, but this is because the origintal turbo takes a beating, when you charge it with about 2 bars.
It is possible to take out about 335 hp from the OM617A by this method, but the original automatic gearbox can`t handle more than about 280. The manual gearbox can take even less.
Check out these videos. He runs 39 inch tires, and axelerates from 40 to 90 km/h in about 7-8 sekonds. And in the sekond video, you can see that he does not have a problem with turbo lag
http://www.youtube.com/watch?v=8X6NlIP-29E
http://www.youtube.com/watch?v=HDpN2NHl3qo
If i can raise the cash, this is to be done to my G as well. "