I've noticed a few conflicting paint code numbers for Sonic Blue. It seems that the SVT has a specific paint code of S1, while all other cars have SN. I'm not sure if there really is a difference between the two paint colors. In any case, your best bet will be to go to the local paint shop anyway.
Mine: 2008 Saab 9-3 Aero SportCombi XWD: 82k, Black, MANUAL
Gone: 2002 SVT, #1654
Hers: 2010 Focus SES: 70k, Ebony, Auto, Moon and Tune