+1 I'm currently using the KZ ATE. (around $10)All round it's the best IEM i've ever owned and has astonishing sound quality for the price. (I also own Atomic Floyd Hidef Jax and Philips SHE990 - both very respectable IEMs)
You could try holding the cups together and take a hair dryer to the headband, then let it cool down in the 'clamped' position... (?)
I have no idea if that would actually work... also you might have to take care not to overheat the headband sponge.
I've read about them only.
I thought it was interesting how they had a driver distance adjustment feature so adjust the soundstage and perceived frequency response.
But I was never curious enough to buy one since they usually sell for more than I'd like to pay for the kind of sound quality I expect from it.