During a special in which country’s brightest stars provided performances from the comfort of their homes, longtime friends Brad Paisley and Darius Rucker provided one of the highlights of ACM Presents: Our Country on Sunday night (April 5), singing together in separate states.Strumming an acoustic guitar and singing “Mud on the Tires” from the back of his pickup truck in Tennessee, Paisley threw it to his pal with the tap of an iPad and a “Take it away, Darius!” Soon Rucker -- coming from Charleston, S.C., in a rocking chair, fitting of the song’s hook -- was singing “Wagon Wheel” with Paisley accompanying him remotely, resulting in a loving guitar duel from two of country’s biggest headliners.