The Matrix was first introduced in the 2003 model year and based on the Toyota Corolla platform. Relatively unchanged in 2004, a facelift for 2005 brought minor revisions to the exterior – mainly revised styling to the front fascia due to complaints of rubbing the ground on the previous incarnation and replacing the red lenses on the taillamps with clear ones. Also, the center instrument panel was slightly redesigned and featured a Toyota head unit in place of the previous GM-sourced radio.