Hi Steven,
Thanks for the writeup and it is an interesting read on the JPlay as usual but for 99 EUROs on this add-on player to achieve greater sonic fidelity based on the idea of switching off non-critical background processes, why not try Fidelizer (with 3 preset levels of background-processes optimization and a custom mode). I had tried both and I personally prefer the Fidelizer with my subjective taste in audio fidelity. Anyway, it is a free download and you might be surprised at what a free software can provide!
http://www.windowsxlive.net/fidelizer
p/s: You can also try both Fidelizer and JPlay simultaneously too!
Ivan