GTS offers a Triangulated 4 Link and a Parallel 4 Link with Watts bar. These 2 types of 4 link designs are proven designs and popular with drag races, street/strip machines and even pro-touring/road racers.
While there are some differences in how they work, both are good upgrades over the factory leaf suspension design.
A triangulated 4 link is a rear suspension that uses 4 bars, also known as links, to hold the rear axle in place under the car and help the rear end articulate in a way to gain traction. It uses 2 bars under the rear axle that mount forward of the rear axle on the frame rails. There are then 2 upper links mounted to a cross member at an angle toward the center line of the car, which is where the term triangulated comes from. By triangulating the upper bars, this allows the bars to keep the rear axle centered in the vehicle, thus eliminating the need for a panhard or watts bar.
A parallel 4 link is similar. It uses 2 bars under the rear axle that mount forward of the rear axle on the frame rails. However, the upper 2 links are mounted parallel with the frame. Because of this type of mounting, this type of suspension requires some type of axle location device in order to keep the axle centered in the car. This can be achieved by the use of a panhard bar or a watts bar. When choosing which type of location device to use, it is important to understand how the axle will move under load. For example, an axle mounted with a 4 link parallel suspension with a panhard bar will up and down as it articulates, but in a slight arch based on the pivot location of the panhard bar. A watts linkage set up will move straight up and down. What this means is that the watts bar allows the use of tighter tire to body/frame clearances. The parallel 4 link with Watts bar is fully adjustable with over 8 inches of rear roll center adjustment. The brackets and links are designed in such as way as to allow finite adjustment with simple hand tools. Ride height is also adjustable allowing the user to determine his/her own stance and performance.