Just read your last message...the problem happens mostly at take-off but also occurs when sitting on a constant speed of around 100kMh ..this is sometimes hard to repeat at 100kmh because it only happens at a constant speed with no acceleration (ie: cruising on a flat section of the freeway ) .they tell me that it is a resonance issue when the turbo is switching between boost stages of the twin stage turbo...blah, blah, blah...I don't care what it is, I just want it fixed..I have had people in my car asking me what the noise is and at times it has been so bad at 100kMh that I have thought I had a flat tyre..Nissan know it is a problem..they are just hoping that I will give up and accept it...NOT LIKELY !!!!