You cannot upgrade a 1SS to a 2SS!
The 2SS has a totaly different sound system, special lights in the interior, Leather seats, and the top technology which includes the USB port and Universal Remote. Which I love and use btw.
I did not get a 2SS to say it was fully loaded, I got it because of the options. To say it is the top line Camaro is just a little gloating one can do, but either way I did not get it because of that, got it because I wanted the options. The BA sound system is better than my other car's Bose system, imo. I love having power seats and leather, and also love driving at night with the neon lights on the dash and doors.