Astro Replacement

[Potart]

Hello friends.
Recently my Astro A40's broke (big surprise) and now I'm looking for a replacement.
I like the Sennheiser G4ME ZERO http://en-us.sennheiser.com/g4me-zero and the Audio-Technica ATH-ADG1 http://www.audio-technica.com/cms/headphones/97d660ada89c32c8/index.html.
That being said, I have a couple questions.
 

First things first, I'd like to stay at $300 or under total. I think I would prefer a headset, but I have heard very good things about modmics.

1. I know that these headsets use the same drivers as some other headphones. What would the modmic alternative be?
2. Right now I'm using the on-board optical out from my motherboard http://www.asus.com/us/Motherboards/Z87PLUS/ to the mixamp (which still works). Will this push enough power to the headsets? (I know the G4ME ZERO has 150 ohm impedance)

3. Any other suggestions? 

 

Thank you

[ShearMe]

1. HD558 is the typical recommendation to replace the headset a from Sennheiser, or the HD380 Pro if you desire closed back. ATH-AD500X for audio-technica, but you could probably spend more on the 900X or 1000A if you really wanted.

2. These headphones will run fine off onboard unless your integrated sound is defective somehow. Only get another solution if you hear some kind of distortion that annoys you or if you desire more volume.

[xtroria]

This may go over your budget a bit, probably consider:

AKG K7xx, Mod-mic, SMSL amp