I am currently experiencing pinking with my 330i - well it seems to be pinking, was originally thinking that it was the dual mass flywheel since it sounds like a rattle, but both Auto Atlantic and SMG say that what I am hearing is mild pinking. Now from low revs under moderate load it does this, but generally around 1800 - 2500 rpm too. You have to be driving in a relatively quiet built up area with your window down to hear this.
Now while the engine pulls strongly, there are two noticeable hesitations while going through the lower to mid range revs - so all that I can think is that our fuel is just a tad too watered down for liking of these engines! Also, I have always heard this pinking noise since I've had the car, but it was very seldom, but lately, since the last few months it has been a fair bit more noticeable - then again, I have also been a lot more attentive and aware of this.
Another thing, I have been running the car on Engen 95 ULP since late last year, but have just switched back to Sasol 95 ULP to see if there is any difference which so far there isn't.
Did a google search and found a thread on a Z4 forum discussing this with the Z4 3.0si which also uses the the N52B30 engine...