Hi Arno,
Your HDD is 40 Gigs, right ? (how many songs do you want to store there? )
MP3 is a way of compression in which you always lose some quality compared to WAV-format.... so I think it is a 'plus' T2 uses WAV. (excellent quality)

The USB interfaces are USB1 standard what means a few minutes to transfer WAV data from T2 to PC. (I wonder why Yamaha did not put a USB2 in it... what is about 10 times the USB1 speed)