I'll be interested in knowing if the E17 is any good with the DJ100. I'm sure it is.
The ODAC I have is perfect for the DJ100 too and doesn't change it a bit. Only major difference is that the bass is even better. Can't even really put into words as to how.
Soundstage is about the same as it was with the HRT MSII with the DJ100 at least.
Unfortunately my HRT made the DJ100 too bassy/warm. Kind of muffled the sound up a bit. Nothing too bad and I still liked it. I guess it's just preferences since I also disliked the HRT with my HD-598/580.