I don't EQ as W2s is an ok one, but ultimately dips vol and quality resulting in making fine iems much cheaper sounding than what their intended tuning and price suggest.
There's definitely a lot of fun to be had with a Cowon or PaW EQ systems and it did miracles with the treble lacking Fearless Roland i just sold, otherwise one of the finest iems I've heard.
But i tend to get iems with a tuning in bass, treble (mids i care less somewhat, such an overstated term lol) and pair them with a device that in Flat/normal needs no reinforcement.
Such exactly is the case with W2/Mest2, a pairing of high quality that brings the best of both.
One thing I've noticed though is the Filter system b/n NOS and any other one changes sound noticeably like an EQ, slow filter is warm, bassier and slightly dirtier/fun sounding than NOS and depending on which one i select, it then has an impact on Tune 1/2 settings, essentially you get about 4 different sound signatures