I finally took delivery om my P85 today. It's a stunning car in many ways. One thing bothers me a bit though: at high speed the engine is pretty noisy and that's not what I expected. It's a deep monotone noise, coming from the back. It appears at speeds over 100 kmh (62 mph) and starts getting noisier the faster the car goes. At 120 kmh (75 mph), which will be my daily cruising speed, it even sounds like an ICE! If I close my eyes I can't tell whether I'm driving a Tesla or an Audi. My Volt is very quiet at such speeds, so I had expected the Model S to be at least as quiet, if not quieter, but instead it produces a pretty intrusive sound. I do have the parcel shelf, so that doesn't play a role. It definitely doesn't sound like tire noise. Does anyone have the same experience with their Performance? Is this sound normal or should I have it looked at?