Not trying to be negative here, but is it quite accurate to say that all the improvements you guys are hearing are due to amping? Since you can't isolate the amp section from the DAC section on the E10, there's no way you could really know this... Especially if your comments are based on the sound with the bass boost on. It is true in my experience however that a good amp can do very nice things for the soundstage.
Also, I don't know if anyone else is bothered by this, but personally I find it annoying when with these headphones, being so sensitive, I can barely turn a volume knob to 8 o'clock or 8:30. In some cases this could run the risk of channel imbalance, and volume may go up in "steps" and not be as finely controlled as wanted/needed. You may want to try a resistance adapter. I've been using some with my HM5s, and now I can go up to 9 or 11 o'clock depending on the impedance used and the amp, and have much finer control over the volume level. I didn't really notice any changes in the sound, but I haven't really done any critical listening or A/Bing. They can be had on eBay for a little over $10.