^ I've achieved the same damping via digital convolution as with physical modding, obviating wualta's creed that no amount of EQ will give the same effect as physical modding, and re-evaluating the degree to which we're limited purely to physical modding in efforts to make these phones sound better.
As such, one is free to punch the drivers into whichever cups and still be able to return the sound to its original balance - most likely.
This is where life gets interesting. Personally, I have found that most of the results you get from modding can be replicated or bettered by designing pads that actually fit the users head and doing you're damping and venting there rather than in the cup itself.
To your point, an interesting experiment would be to create anechoic cups and see what convolution can do with them.