You have the option to use a combination of 17 heads (8 with respirators and 9 with berets) and ammo pouches, knives, grenades and canteens to fully customise your miniatures.
If you choose to build a squad of Tempestus Scions you have the option to upgrade 1 model to be a Tempestor. The Tempestor has a fantastic array of weapons options. The right hand can be equipped with a powerfist, chainsword or power sword, and you can choose to upgrade the left handed laspistol to a bolt pistol or a plasma pistol.