Originally Posted by AM03GT

The arms make a pretty big difference as they offer different shock positions and add more as well 6 vs 4. I currently have 6.1 arms on my car with regular 6 hubs and steering blocks and the change allowed me to use a suspension setup that was unavailable on the original arm (the "c" shock location on the lower arm).

The offset arm mounts are also nice as the built in 2mm offset allows for setups with less shims which give positive thread engagement without having to use a very long screw. In most cases a shim may not even be needed which increase surface area of the mount to the bulkhead...