RAW does NOT support in any way shape or form that a cybertorso EVER replaces your actual body score. p343.
Wow, if you actually read what I've said from before at all, you'll see that I agreed the character still has a natural unaugmented score for each attribute. The cyberlimbs don't
replace that score. Instead they determine how that score is figured for any tests/tasks that occur. This is all blatantly in the cyberlimb text. I've quoted it a dozen times. The character has the attribute, but it never gets used if he has all limbs replaced. This is because of this section, that I've quoted here: "use the attribute for that limb (natural or cyber);
in any other case, take the average value of all limbs involved in the task (round down). If a task requires the careful coordination of several limbs, use the value of the weakest limb."
If the attribute figuring is not decided by one limb, it's decided by multiple limbs. There is no case of a zero limb test. Yes, the character has his natural scores still, but any test/task being attempted is going to have it's attribute figured by the attributes of his limbs. If all his limbs are cyberlimbs, his natural will
never get figured in.
In the absence of any text to the contrary CHANGING this... the player still ALWAYS has those natural(augmented) stats! The raw states the cyberlimb/shell ALWAYS has it's own stats INDEPENDENT of those stats of the base character.
Seeing as how this is the basis of this point of attack, and I've already disproved it repeatedly (again above), you really need a new angle.
So you take the ONLY thing in the game which solely affects flesh such as a neurotoxin... then rule that the cyberlimbs help. Great that's your descretion as a GM to say which cyberlimbs help or not. It's also fully RAW for another GM to rule that cyberlimbs don't help at all with your fleshy bits resisting against the ingested neurotoxin stopping your heart.
Uhm...healing, which also isn't restricted to non-cybernetic. Drugs, which likewise aren't restricted to non-cybernetic. Toxins aren't the only thing, just the one you have the biggest focus on. And no, it isn't RAW for the GM to put extra limitations in. Doesn't matter where it goes, or how you twist the wording of it, there is no RAW stating this limitation to flesh only, so it would be a house rule.
When the Body stat test is called for.. .the GM DETERMINES if each cyberlimb (including the torso/skull shell) are included in the Body stat (cyberlimb only, weakest, average). That is direct RAW from the cyberlimb section.
He determines if each limb (natural or cyber) is included in the figuring of the attribute. He also must choose one limb, or multiple limbs. No limbs is not an option (and would result in a 0 attribute if it were).