If u half it, it could cause problems with egr. Too low of pressure and it can cause problems, but since u are going after cat and not making a real dual exhaust it shouldnt be a problem. But anyways, should be ez, after the Y pipe u just need to route the pipes so that it wont hit the travel of the back axle. Fab up some hangers, and that should be it. Might mess u up when u go to get your car smogged so i would check that out.