Air... yeh, that's what I think I feel like I'm missing from redbook playback on the philips player. BUT, after almost 6 days of continuous playback, the sound has opened up some, and become better integrated within itself.
the midrange is probably it's best trait, the high end needing the most help.
In asking for mods, I'd look for someone who could open up the top end, add some air, and remove some of the overall coloring the unit has... there just seems to be a little bit of a thickness to the sound. I'd also ask to see if the soundstage could be expanded... the sound is full, but doesn't extend far out on either side.
All this said, the unit sounds much better than it originally did, even two days of continuous playback. my ear did hear improvement over time.