The full rules proposal for upgrading warcaster armour can be found in the Gearbooks II and III PDFs.
Spike Overloader [Warcaster Armour Upgrade]
Cost: 300 gc
Effect: While a suit of warcaster armour fitted with a spike overloader is running at full steam, during their Control Phase the warcaster wearing and bonded to the suit of warcaster armour may allocate an additional point of focus to a single steamjack in their battlegroup, even if this exceeds the maximum number of focus points that can normally be allocated to the steamjack in question.
If a steamjack begins its activation with more than its allowed number of points of focus because of the use of a spike overloader, it suffers 1 point of damage to its first available cortex system damage box at the end of its activation.
Power Requirement: 2
Installation: Installing a spike overloader requires one hour of labour followed by a successful INT+Mechanikal Engineering roll against a target number of 14.
Fabrication: The material cost of the spike overloader’s parts is 100 gc. It takes two weeks to construct the device. Fabricating a spike overloader requires the Inscribe Formulae ability as well as a successful INT+Mechanikal Engineering roll against a target number of 14.
Comments welcome, as usual.