not sure, but
The griffin pod buds or isounds or whatever, snap on, bass enhancing thingies suck. All three sizes are equally uncomfotable in my deformed?! ears.
It is true the bass frequencies are enhanced since they are jammed into your ear cannals, but the wind noise is enhanced and the sound of the earphone cables as they hit stuff like your clothes as you walk is also enhanced. yep, there is a physical connection between your ears and the headphones and the wire they are attached to too.
I have a shuffle and Lindsay has a mini. Lin uses the Griffin airtunes to broadcast via FM to her truck and I plug the AUX in from my head unit directly into my shuffle so I can go PODDING in my 4runner or in her Chevy.