I have done a soft mod after reading about the improvement in trebles when you put the pads upside down. It was working indeed, however magnets wouldn't hold the pads. The problem was about foam absorbing sound waves especially in high frequencies. When you put pads upside down foam part doesnt intervene. So I just inserted little pieces of paperboards between the pad's case and foam. You can see in the pictures. The result was impressive, the trebles isn't sparkling yet they are more forward. The characteristic of the earphone became way more warm than dark which was before.
Here are the pictures: