Well I record to WAV cuz 1st in traktor u only can do that. (btw in traktor u have a lvl meter for the rec)
and cuz it sounds so much better than mp3, I buy in the itunes store so its in AAC, and idk
I did record with an external program when i didnt have tr2duo and so i did with mp3.
WAV sounds so much richer, its just better than mp3,
and to answer your question if the qualy is subsistent: yes it is, iTunes doesnt change it at all, only if you wanted to put it on a apple device it would convert it automatically since those dont support wav