Why do you want more power on the amp?  From your review - you don't own any headphones that need more power than the X5 supplies.  It had no issues at all with my 250 ohm DT880s or my HD600.  Curious as to why you'd ask for more power - when the immediate result would be less battery life ..... ?

My first comment to my first review - thanks.
To answer your question I should have perhaps explained a little more why I 'felt' that I needed more power.  I found that I had to turn the volume right up to get the level I wanted  (around 80) when I was expecting to rarely go over 50 or 60.  I realise it could be a things like the quality of my music files or more of a psychological barrier (a high volume setting equating to distortion - obviously not accurate) or the type of music I was listening to or I could just be deaf!
I should probably rectify these possible reasons first and if I still feel that I need more power I could buy an amp.  All these things are subjective to a certain degree but I agree with you that I would not want to take a hit on battery life.

My only qiestion is you brought up you used a ipod and fiio amp before the x5 and never explained which set up you like better.

wilman0527 - thanks for pointing that out. It seems some text got lost in my copy paste.  I have added my preference - X5.  And that preference is getting stronger.

I played with it around yesterday and the system got stock after 1 minute
I guess they will have a lot of firmware updates coming.
Did you encounter any lag/got stuck?