cable should be the last place to put money into. and you should do it for comfort or microphonics more than to hope for a change in sound.
if I had 200extra bucks, I would buy another headphone. I'm sure the benefits of 2 differents phones outclass the benefits of a cable. in my case I use the IE80 to relax in calm environement, and put on a pair of etymotic for maximum isolation. those 2 phones couldn't be more different, but I "need" both.
then again some cables are just so pretty ^_^.
I bought my stock IE80 for 190 pounds.
Invested into custom sleeves and upgrade cable for another 190.
380 all together...
I can tell, both my upgrades improved the performance a lot... (20-30% each, so 40-60% all together.)
I do not really think, you can buy 'better' sounding stuff for 380 pounds.
Different maybe, but not better.
If you want better sounding, you should pay double of what I spent. (6-700 pounds)
And I am not entirely sure, that would double your listening experience as well...
Of course, everything just depends on your budget...
But I do believe, I got the best sounding for the price I spent, and eventually this is, what matters... ;)