I gave up and installed the Pioner AVIC-D3 with iPod adapter. The ipod interface is outstanding, which was my number one goal.
The installation and hookup does have it's technical issues as is noted on other threads here and on AVIC411.com (Onstar retention, chimes, RAP, steering wheel control, Onstar volume, VSS,etc.). Thus it is not comparable with the quick and easy install (and removal
) of the Nucleus unit.
Good luck to all, I hope A.I. can fix the bug!