Answer
The 9-3 is about 600 lbs lighter than a 9-5. the 9-5 has the 2.3 turbo motor & the 9-3 has the same motor with less stroke on the crank throws - ie it is a 2.0. 9-5 is the large euro sedan & the 9-3 is more of a mid-size ( it is not a compact). the 2002 & earlier cars are swedish & the 2003+ cars have better bodies - but have the general motors cobalt engines are in the 9-3 while the 9-5 still have the excellent swedish turbo intercooled turbo motors.