It could be the final drive (ring and pinion gears).  The noise is not dependent on revs or which gear is selected right?  It is only dependent on the speed of the car?

How many miles (or km) on the car?  If it's very new, the noise may improve with more use.


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73 Carrera RS 2.7 Carbon Fiber replica (1,890 lbs) Former: 73 911S, Two 951S's, 996 C2, 993 C2