I have owned my 2015 Convertible 220i for a few months and recently changed the front run flat tyres to Pirelli Powergy hoping that would reduce road/tyre noise. It made know difference. Have riden in a couple of similar models, it seems to be a characteristic of the model. I like the car in all other respects and so am considering adding sound proofing, particularly to the front wheel arches. (the noise- a drone/rumble) Dose anyone have experience of the effectiveness of additional sound proofing and if so which arears give the most rewarding results Many thanks DavidEM