[Fungus]

I'm having a hard time deciding which version to get. 
 
I know the 13 II is 600ohm so is harder to drive plus the fact it has a longer 3m cable and straight angle 3.5mm jack. 
 
I also own a Fiio E11 amp and don't use it very often and want to make use of it.  
 
I know that straight out of a portable dap, the standard version will better but what if use it with my fiio E11, will the 13 II sound better? 
 
Where I'm buying from, both are the same price. 

 

[CJG888]

I doubt that the E11 will work well into a 600 ohm load. Generally, 300 ohms is about the limit for portable gear.

The 13 was designed to work with studio equipment (where 600 ohms is / was the standard).

The standard HD25 can be bought with a variety of cables, however (including longer curled cables).