If you are just using a single deck to remix, via locators, then setting the faders at unity, or 0db, should record at the same level as the original audio. As soon as you start using a crossfader, eq, filters, and FX, you will have gains or losses in the volume level from the original.
Although I don't consider Cross to be a DAW remix solution, it would be more than adequate to make edits and the like.
I am also highly concerned with audio quality and fidelity through my system, and I can honestly say that Cross has one of, if not the best, codecs for time-stretching and playback. I would run an mp3 through your system, recorded through Cross, and then compare the files in an audio editor to see what the difference was. I'm fairly certain they would be exactly the same. Albeit in mp3 quality.
