IIRC the S4 arms are even longer than the B-Max4III arms. I've used the B-Max Arms on my YZ-2 and it helped against traction rolling when I pushed too hard on high-grip astro and carpet, and it became even better with 1 mm wheel shims in the rear and 0.5 mm in the front. I am not surprised to see all these arm options, Shin did the same to the Lazers and Ultimas when he used to be with Kyosho. It's a great way to adjust the cars to a wide variety of tracks!
