[min]

Hi,

Thanks for the quick reply! About the color - congrats for yours too (yours seems also the Donington grey?); not to mention your incredible looking 21" rims (for the moment I remained on 19" for comfort reasons, I'll see in the future if I switch to 20").

Getting back 'on-topic' : as mentioned, I plan to do the tape-test whenever the wheather improves a little. Fortunately for me I am not as affected as in your case: it's only the upper driver's door frame area which generates some low volume but still annoying wind draft noise (it is covered by the music if I increase the volume like 30-40% upwards). So I hope the test will quickly reveal the fix (which, I guess, will consist in replacing the window seal). One more test that I did and which might be helpful in your case: I attached a suction-cap phone holder on the driver's window and pulled it towards the interior of the car while driving. The purpose was to understand if the door is not sealing/pressed enough against the car frame/seals and me pulling it would seal it better; though it didn't seem to improve (perhaps just a little bit) - that's why I still suspect/hope it's from the window seal which is not 'embracing' correctly/completely the whole window...

About the windows versus insulation - it is not clear to me if I have the acoustic package; though "S356 Climate Comfort Laminated Glass" and "S358 Climate Comfort Windscreen" are listed for my car - perhaps they are just for climate protection or they include also the thicker glass? I am away now but in the weekend I'll be near the car and I guess I can easily lower the driver's window and see if it's double layered for the acoustic isolation...

One last word about the additional car body sound-proofing: I did some on my previous car (Alpina D3 - based on F30 model) during a major sound system upgrade. Basicaly lots of Dynamat sheets were inserted in all doors/panels, on the floor of the car and in the trunk&trunk lid. The effect on highway speeds were visible (especially much lower tyres noise) but wind noise (especially around windshield/sunroof/side windows) was still present (as expected). Ok, the sound-proofing was not done to the level mentioned by you (including roof, seals etc) but my advice is to try and test 2 similar cars/models (like also a G31 without sound-proof and then your brother's car) in order to take a better decision and adjust your expectations from the sound-proofing. If you conclude that the noise comes mainly from the windows/doors seals - I guess the acoustic glass would be the solution for you. Also you mentioned that that specific workshop can help also in improving the door/windows seals? Then definetly I would start with those: on one hand the work is less intrusive then dismantling the whole interior and, obviously, the costs will be much-much lower than the initial quote for the whole car's sound-proofing. I would be confident that acoustic glass plus the door&windows seals extra insulation would do the trick for you. On the other hand the visco-elastic insulators for the whole car (like Dynamat used in my Alpina for doors, floor, trunk) will add some tens of kgs to the weight of the car (in case you are obsessed like me of weight/performance/handling etc); and the facelift 7 comes indeed with lots of 'wool' based insulation (which is a light weight material). And it's not just marketing: in December I dismantled the rear seats and all trunk side-panels in order to install the ski-loading door and I can confirm they used indeed quite some amount of insulation. So for your car my bet would be towards the thicker windows and door/windows seals...

And just to add on the debate about acoustic glass role: 2-3 months before buying my car I tested also a similar facelift 7 series but the V8 - 750i (someone wrote that all 750i have by default the acoustic glass?!) and I am tempted to say that the road/wind noise was a little lower in that one than in my 750D?! It might be as well that I was testing it immediately after a long highway trip with my Alpina and on the spot the difference was quite big while now I am comparing my 750D road/wind noise with the similar noise (from my memory) of the 750i tested several months ago...

Good luck with your tests and next actions, I'll post my results as soon as I have news.