I really wish you wouldn't have said that. There is this guy in Brooklyn who is selling a pair but I really can't find the time to get my butt down there. If they really are that amazing then I guess I have to make a sacrifice. I know headdirect offers a 30 day money back plan but I don't want to have to deal with shipping them back if I end up not liking them. Then there are these v moda that everyone is going on about. Radio shack should have a pair when they officially launch correct? Maybe I should just pick one and call it quits. This is just to hard of a choice.
Just know that you may be missing out on the absolute most enjoyable and high-quality bass response outside of a few out-of-reach exceptions (LCD2/3s, well-driven HE6s, and a few dynamics/stats maybe), and achievable straight out of your E17. Mids and treble are also tuned to be a balance between realistic/neutral and fun, with the ortho magic that is exceptional instrument separation and effortless resolving power.
If you buy any 2nd-hand HE400s though, make sure they are not rev3, as it is a recalled revision that has an acoustic flaw.