The four remaining "American Idol" contestants will take the stage next week to perform rock songs -- and not only will there be a special mentor, but there will also be some exciting guest performers! Famous rocker Slash of Guns N' Roses and Velvet Revolver will take the four hopefuls under his wing for next Tuesday's performance show. The following night Wednesday May 6, No Doubt will perform and Daughtry, will return to the "Idol" stage