THE proof of the efficacy of Saab seats is in the driving and most passengers will find they remain comfortable after hours on the road. The seats are essentially the same as those used in the bigger 9-5 model, which means they do intrude a little more on cabin space than the seats used in the 9-3's predecessor. In the Aero, leather trim with patterned inlays is standard, as is a three-position memory on the driver's side. The cushions and backrests of both front and rear seats are more deeply dished.