The long travel DC-4 a-arms are +2.5" wider and 1" forward and feature the easy camber & quick caster adjust-ability. The ball joint works on a slider with a nylon jam nut so the camber can be adjusted with the ball joints still intact. The caster is now adjustable to 3 popular positions using special spacers so no extra tools are needed. They use longer shocks for better valving. The 2006 TRX A-arms are 1/2" narrower and have a plate with a star on the upper a-arm to help identify them. A-Arms are backed by a LIFETIME WARRANTY (excluding normal wear items).