The diesels pull for england in any gear, and certainly feel like more than 143bhp!!
I was looking at a 325TDS to replace the Rover, but decided to run it in to the ground before buying a new runaround.
The 2.5 TD is the same lump they fitted in the Omega TD and is very strong and reliable, though I was shocked to find a diesel pump cost over £500 when they go wrong
LSDs can only be found on the "Sport" models, and non of the diesels have them.
I belive chips can take them to 170bhp-ish