It is tempting to put mod chips, many people here use it (from dastek, racechip, etc) to their diesel cars and works really well. Power and economy is improved as advertised.
To be fair, the best selling diesel SUV here is Toyota Fortuner 2.5 D4D with only 102hp/259nm and Mitsubishi Pajero sport 2.5 DI-D with 136hp/314nm (turbo version, no variable geometry) and 178hp/350nm (variable geometry turbo version). Both are similar to a BMW X5 size-wise and both are 7-seater body-on-frame suv, so naturally it felt underpowered with those power figures.
I haven't seen BMW diesel with chiptuning yet. I was tempted at first, but then I felt 184hp/380nm is enough for me, at least for now. I don't think it's worth risking voiding the warranty, again, at least for now
