I have decided to sell my Xonar STX because i no longer use my PC for music, having moved to a laptop.
Purchased new, this card works perfectly as expected and has never been out of my PC, sadly do not have the original box but it will be packaged very well and securely as to arrive in perfect condition.
Price includes PayPal fees and shipping to UK, although i will ship to EU for an extra £5
Thanks for your interest,
Additional feedback: http://www.head-fi.org/t/465406/4lx