Q: Do I need both the Fore arms and the Lateral Aft arms?

You can buy them separately, and which you need depends on your symptoms. The Front Lower Compliance Fore arms carry one spherical bushing and one ball joint each and act as the factory caster adjuster. The Lateral Aft arms carry two spherical bushings and one ball joint each and serve as the factory camber adjuster and the lower strut mount. Owners chasing a full front refresh often add the adjustable front upper control arm set as well; a targeted repair may only need one lower arm.