The Competition Series Engine Mount Bushing Kit is designed specifically for IAG Subaru EJ engine mounts. IAG’s engine mounts feature the ability to swap bushings for street or track use. The Competition Series kit includes (x8) 90A durometer bushings that are stiffer than our 75A Street Series Bushings. The 90A durometer bushings help to greatly reduce the forward and backward movement of the transmission and engine under hard acceleration. Due to the higher durometer, additional NVH (Noise Vibration Harshness) is perceivable through the interior.