the side draught depending on manifold will need a slight cut taking out the the brake booster arm nothing serous, but the sounds will be worth it allso power is slighty more smooth, depends what's done to the motor, if you use a 32/26 on a gt manifold with a warm cam, you will get a lumpy idle due to the different size chokes, unlike the dcoe, but when it comes to fitting the gt manifold is straight bolt up, i would go the sidedraft me self :)