These Gr A trailing arms had an extra member connecting the two "legs" of the "V", turning it into an "A". At first blush this would appear to be similar to what is currently done on the BMW M Roadster/M Coupe. However, there is a subtle difference. In the case of the M Coupe the reinforcement is engineered to handle compression, tension and bending forces. The reinforcement on the Gr A car (which is really no more than a "rod") is primarily designed to handle tension loads. The reason for this is apparent from the photo below. The attachment method used for the outer trailing arm pickup point does not locate the rod end in the lateral direction. The rod end is free to "float" laterally, which it has to be as the distance between the inner and outer pickup points changes as the rod end is screwed in or out to adjust toe. But to keep the trailing arm from "spreading" under load, the Motorsport boys welded in the tension rod. The newer style M Coupe trailing arm reinforcement achieves the same effect certainly, but it does a lot more, acting in compression and to some degree in bending as well.