Just appearance. The dual tips are nicer looking because of symmetry in my opinion. The cars all have a single exhaust manifold so there won't be performance differences that are exhaust related. The dual uses a Y to muffler and tips where the LS/LT just have a single muffler and hidden tip. The biggest difference is the LS/RS/LT have the 1.5T with CVT and the Premier has the 2.0T LTG and 9-speed. Another major cosmetic difference is the LT/Premier have the separate LED DRL and LS/RS have halogen headlights as DRL. I attached the 2022 ordering guide and pictures.