Thanks OK-Guy. Do you perceive any sound difference between line out and headphone out with all 'enhancements off'?
I guess the line out has been correctly implemented based on your comment, so probably the best option.
Are there any decent WM-port cables; only I only can find cheaper ones (might be perfectly fine) on Ebay. The Fiio one is a better option though - their iPod line out cable was excellent, but I'd happily pay more for a higher end cable.
There are two options connecting via line-out... first is the FiiO WM-Port cable that you quoted, which is excellent... the second is via Sony-LOD (link below) using a mini-jack lead, I have a custom-made copper/silver mini-jack cable & a Magnus one, I can't hear any differences between the three of them in truth.
There is a slight difference between the two, using the ZX1/PHA-2 combo the music appears to have more air to the music & the bass seems a bit more punchy (better defined?), hth.