etymotic er6 or er6i for ipod

Which is better for me? According their website, er6i has lower impedance and higher sensitivity and max SPL.
But I listen at minimum volumes.
The 6i is specifically made for the iPod and with its limitations in mind, so if you are not using a separate headpone amp with it, I would recommend the the 6i. In particular at low volume, it will give you fuller sound with more bass. Besides, it seems to have recieved better reviews anyway. Just make sure you get a good seal in your ears before you judge them..