I know the Impala SS cat backs won't fit wagons without some changes. It sounds like they are ok from the cat to the muffler and need changes downstream from there. Is the difference in the part that goes over the axle or just longer pipes from the axle back to the bumper? Is it feasable to just alter the SS cat back or better to just have them bend the pipes from scratch? I have a Dynomax cat back on the SS and love it, would like the same for the wagon.