Originally Posted by Chris Jarosz

Alright here's the best way I can help with the arm situation.

Attached is a picture of the current selection of arms.

The top one is a carbon arm. The stiffest arm, it is signified by one swaybar mount ball (B4 swaybar, not B44), and a very light color.

The middle one is a B44/B44.1 arm (the materiel did not change between vehicles). This arm has more flex than a carbon arm but less than a B4.1 plastic arm. Notable differences are, glossy color as well as a cut out on the webbing of the rear hub along. If you look very very closely you can see rectangular indentations on the top of the arm from the mold.

The bottom one is a B4.1 plastic arm, the softest arm made. A dark dull color as well as no cut on the webbing and two swaybar mounts are the best way to recognize this arm. Again if you look very closely you can see circular (as opposed to rectangular) indentations from the mold.

The original B4 plastic arm (older materiel) isn't produced any more but can still be found at some hobby shops. It has one swaybar mount and looks exactly like the carbon arm, just a darker color.