you are right about headphones has more influence on SQ than dac/amp.
But if you carefully choose a dac/amp, you would be able to use it for couple of years. The initial investment may be little higher, but it is worth rather thinking of spending for another dac/amp after few months.
In my case, I bought E 17 at the end of august. It is good for driving K 240 mk ii, but after buying HE 400, I started to wonder whether HE 400 gets full benefits from E17. E 17 can drive HE 400 loud enough, but SQ?!
I was considering Modi/magni stack and aune T1 for an upgrade from E17. T1 may need running cost for changing tubes and tube rolling. But at last, I have ordered Audio GD 15.32 few days ago. It can drive wide range of cans.
What I can suggest you is spend sometime to read about each product that you have sorted out.
I would also suggest you to consider Audio GD 15.32 in your list. It can be shipped to anywhere in the world, check this page, http://www.audio-gd.com/Pro/Headphoneamp/NFB1532/NFB15.32EN.htm
Edited by rubinstein - 12/7/13 at 5:09am