Thanks for the responses. Yes, I saw that audio option (Hi-Bit32 i think), but I'm really not sure what it actually does. The manual states "...and the high frequency data is interpolated..." I haven't A/B tested it to hear it's effect, but based on the description, it's definitely resampling or doing some other transformation of the signal. Requantization from 8/16/24 bit to 32 will do absolutely nothing (beneficial or otherwise) to the signal, so for this option to have any effect at all, it MUST be doing something else.
Also, there's the Auto Sound Retreiver setting, which seems to overlap in functionality. My guess is that it upsamples lower frequency sources (44, 48, etc).
I might just leave both of these settings off when I'm able to playback bit perfect sources, but enable them when I can't. Since many programs/sources don't support it anyway, they will probably help in those situations.
Great link on the impacts of sample rate conversion: http://thewelltemperedcomputer.com/KB/SRC.htm