Welcome to GenVibe! The ground effects kit will fit any Vibe from 2003-2008. The side and rears were exactly the same, with only minor changes to the front bumper, none of which keep the kit from fitting.
2005-08 models can have the fancy rocker panels. I don't know how the kit's side skirts fit, but you wouldn't likely be able to get them on on top of the flared rocker panels. To see if you have the fancy rocker panels: the fancy ones angle outwards. The "standard" ones curve inwards towards the underbody of the car (not to mention they look way better).
"If you don't love me at my diddliest, you don't deserve me at my doodliest." - User ktluvscricket of reddit