Carlos Ghosn confirmed the 3.5L for the '02 Maxima during the webcast of Nissan's year 2000 financial report, as can be seen here:

http://www.nissannews.com/webcast2/message_arch.html

During the release, he mentions many areas on how Nissan plans to continue their growth. One of which is by updating their models constantly throughout their life to keep competitve, this is when he uses the Maxima receiving the 3.5L as his example.