[Spook410]

They typical real world reference for 70db is a noisy restaurant. Just test drove a 340 a week ago. It was certainly quieter than 70db cruising at 70mph. Maybe the C&D numbers will be overly pessimistic for the M2 as well.

As for 3db being hardly noticeable, maybe that's true in the real world at high sound levels. Certainly not the case in a closed environment running noise generators. In that setting 3db was very noticeable. I think it would be in a car as well. Look at different models that run at 67db that we think of as luxo-cruisers compared to hot hatches running at 70db. At 72db you are now in the realm of old GT500's and Camaro ZL1's. Cool cars for what they are.. but not commuters.