They follow the standard rules for cyberlimbs.
On the Corebook (p.343), the rules for cyberlimbs are:
- They add an extra condition monitor box to your character.
- They have a Capacity, allowing your to implant other cyberwares within (like a Cyber Holster).
- They have their own attributes that replaces your own when used for tests. So, if you are trying to hold or breath you could use your cybertorso's Body rating.
There are also extra rules for cybertorsos among other cyberwares, as requeriments.
The Articulated Weapon Arm (Augmentation p.43), for instance, requires a cybertorso to be implanted first.
An External Mount (Augmentation p.43) also requires either a cyberarm or cybertorso to be implanted.
Also, without a cybertorso, the maximum enhancement rating on your standard cyberlimbs is limited to 3 (Corebook p.343):
Cyberlimbs come in two distinct types: standard and customized.
Standard limbs: These prosthetics are basic off-the-shelf models.
All standard cyberlimbs come with Body, Strength, and Agility attributes
of 3. These values can only be augmented by cyberlimb enhancements.
On standard cyberlimbs, a cybertorso is required to have
cyberlimb enhancements with a rating higher than 3.
So, even the simplest of cybertorsos will allow you to obtain non-customized cyberlimbs of ratings higher than 3, up to your augmented limit. Otherwise, your maximum Strenght, Body and Agility is limited to 6 (3 base, 3 enhancement).
