The big difference between the pre and post update E53 3.0d was the torque, more so that the power. In Australian spec the max torque went from 390Nm to 480Nm while the power jumped from 135kW to 150kW.

The E53 only had one diesel on offer at any one time but it was upgraded with the 2004 facelift. The E70 has had two diesels, single and twin turbo and both have been updated a few times. In all, between the E53 and the E70 there's been about seven different diesel engine variants over the years although this varies from market to market.

Thanks for the replies I was looking at a used 2007/2008. I think I'll hold out for the SD as it sounds from what has been said there is still a substantial difference. That said probably the wrong time of year to buy one

If that's the years you're looking at you'll find the 3.0sd has around 25% more power and 13% more torque than the 3.0d. I'm not entirely sure about UK-spec but I believe it's not much, if any, removed from Aussie spec.

I've driven the two back to back (in Aussie spec) and the 3.0sd is definitely the one to have if performance is a priority. However, the 3.0d is still a great drive and just as effortless in everyday driving as the sd.
What you will notice about the sd is that it's a little more responsive off idle than the single turbo. It also likes to rev a little higher and more keenly than the the single turbo and this is where it makes its extra power. In the mid-range however there's not much in it.

As for fuel consumption, again there's nothing in it for normal driving but if you regularly access the extra power that the sd has then you pay the price.

Good luck.

I feel that the AT in the 3.0sd keeps the revs too high, likes to run it to redline although that really doesn't make use of the fat mid-range of the bi-turbo motor. I usually finesse the throttle to keep revs under 4k.

Where'd you find a 3.0sd to drive around here?

He might just be refering to the 35d we get it in the states. It also is a twin turbo I6 like the 3.0sd and maybe it has the same tune for comparison.

It's basically the same engine except that the US-spec 35d has urea additive system to meet local EPA. Slightly different power and torque figures too.

When did you buy a diesel?

Dad leased one in one of his many random moments of illogical thinking. None of us are happy about it. He's the main person that drives it, but I've driven it on occasion on short trips to the market when I don't want to subject my X3 to cold starts, short-distance trips.