While not certain which model SAAB you're asking about, the addition of lower body panels generally help aerodynamics, by allowing less wind underneath the car and channeling it over the hood, roof and trunk (why rear spoilers are desirable). Think NASCAR but less extreme.
In the case of my Viggen, the body kit and rear spoiler, plus lowering the car a bit with racing springs/struts, improves handling over a similar 9.3 without the extras. In the same manner, a Classic 900 SPG or Airflow car achieves similar improvements, which is why I'll be adding an SPG kit to my Commemorative Edition coupe.
Hope this helps.
In the case of my Viggen, the body kit and rear spoiler, plus lowering the car a bit with racing springs/struts, improves handling over a similar 9.3 without the extras. In the same manner, a Classic 900 SPG or Airflow car achieves similar improvements, which is why I'll be adding an SPG kit to my Commemorative Edition coupe.
Hope this helps.
