This page details the differences between the 2 most popular choices for aftermarket skirting/valence kits.  You can find specific info on each of the 2 kits on their respective pages.

Aero/Vector Skirting

Catalog Accessory Skirting

Thanks to finklejag, JNGold, Saba, enobar, SS & aeroild for letting me steal their pictures off the web!

Pictured below are cars with the Aero spoiler.  Of the two, it is smaller, lower & molds more to the body creating a sleeker line, and more harmonious look.  It looks  a bit like it was molded into the trunk.  It is meant to be paired with the Aero Body Kit.  "Improved aerodynamics and roadholding."  You will probably have to get it painted as it will come primed.  Paint & Installation by dealer usually is roughly $200.  This spoiler bolts onto the back of the trunk.

Catalog Accessory Body Kit

"Provides added stability at varying speeds and gives the car a broader, lower and more potent stance. Tested in the wind tunnel to ensure proper cooling for the engine, brakes and other key components. When combined with a rear spoiler, the lift forces are reduced 70% at the front and 40% at the rear. Must be painted."  -Saab Catalog

Pictured below are cars with the Catalog spoiler.  It is slightly bigger, and creates a slightly more aggressive look.  It is meant to be paired with the Catalog Body Kit.  "Improves the aerodynamics of the car and contributes to a sportier appearance. Reduces the lift forces at the rear by 40%." according to Saab.  You will probably have to get it painted as it will come primed.  Paint & Installation by dealer usually is roughly $200.  This spoiler bolts onto the back of the trunk.

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