Gotta give Nissan some credit for finally realizing there is a problem with the front tire noise.
For those of you who didn't get a letter..."Nissan has determined that 350Z front tires are sensitive to ANY toe-out condition; and if the front toe alignment is not correct on Model Year 2003 350Z vehicles, an irregular wear pattern on the inner edge of the front tires may occur. This wear pattern can cause a tire noise condition described as "tire roar" or "tire growl" which may be most noticeable during low speed braking."
The sound is unbareable, wonder at what point the irregular wear pattern becomes dangerous? Worth getting it checked out.