Actually if your looking for something on the side of neutral with DEEP punchy bass the HE 4 and HE 5XX models should work nicely for you! The HE 4 is like an HE 6 [needs a ton of power] but only costs like $350 if u can find it [it's like a super duper Dt 880 apprently]
I'd imagine they would b very nice! I also really enjoy my HE 400 for EDM. Although it's not entirely as neutral as the HE 4 or HE 5xx variants
Also a correction to this comment... he has the LCD 2 >.> herp derp, has any one suggested he try the LCD 3?
The Mjolnir might hav better SQ but it's stricly an amp, where as the AGD NFB 10ES2 is an dac and an amp for about $100 less [I just got one] so as always it depends on your budget.
Adtionally is the Soloist he is using SE out? Going Balanced out would give him a better sound stage, and more than enough power to drive those headphones very nicely!