The Phantom grip friction style LSD works decent in the GA16. I used the stiffest springs and mine offered decent lock-up for years in drag and road racing. With one in my GA16 I was able to cut consistent 1.80 60' times on slicks. You can also shim it as well. I always thought about machining the side of the spider gear that contacted the Friction plate surface so that it contacted a greater surface area and then shimming it out.