In order to modify a piece of equipment, a character needs the object itself as well as the plans, materials, and tools necessary to perform the modifications. Then he needs to roll an Extended Build/Repair Test using an attribute + skill appropriate to the type of equipment he is modifying. If he rolls a critical glitch on the Extended Test, the modification fails. Otherwise, the modification is successful once he has accumulated the specified number of hits.
In order to begin a modification, the character needs a building plan: a document (usually digital) with step-by-step instructions—to get an idea of what needs to be done.Characters can obtain plans from the Matrix using a Browse + Data Search Extended Test with an interval of 1 minute and a threshold equal to the threshold of the modification test. The cost of the plans is up to the gamemaster, but certain open source or pirated plans might be found for free if the character looks in the right place. A character can also try to get a plan with good old-fashioned legwork (see Swag, p. 280, SR4). Characters can throw some money around to speed up the plan acquisition, using the same rules as given under the Availability Test (p. 302, SR4).
For some obscure or highly illegal modifications, plans may simply not be available. In this case, or if the character fails to turn any plans up or simply wants this to be a DIY job, he can attempt to create his own plan. Th is requires an Extended Test using Logic + an appropriate Knowledge skill with a threshold equal to the threshold of the modification test (see below). The interval for this plan design test is up to the gamemaster, based on the complexity of the modification. It could be hours (test threshold 4), days (threshold 8), or even weeks (threshold 12).
If a character does not have the time or the means to obtain or create a plan before starting the modification, he can go ahead without the plan, relying solely on his basic knowledge and experience. In that case, he doesn’t receive the dice pool bonus for plans.
The materials necessary to do the job are represented by the cost and availability values of the modification, as outlined in the modification description. To acquire the materials, the character has to buy them as he would buy any other item, following all the necessary steps (pp. 302–303, SR4). In order to perform the modification, a character also needs the relevant tools (pp. 322–323, SR4). Depending on the type and overall difficulty of the job, the character will need a kit, shop, or facility of the relevant skill. Each modification description specifies which of these is required. If the necessary tool is not available, the modification suffers an Inadequate or Unavailable tools modifier (see the Build/Repair Table, p. 125,SR4), which may mean that the modification cannot be done.
All modification tests are Extended Tests based on the Logic attribute + the relevant skill. The relevant skill for firearms and weapon modifications is Armorer, while for vehicles it depends on the vehicle type (Aeronautics Mechanic, Automotive Mechanic, or Nautical Mechanic). The threshold for the modification is listed in the modification description, or determined by the gamemaster (see the Extended Test Difficulties Table, p. 58, SR4). The interval is also determined by the gamemaster, using the same table. We recommend a fixed interval of 2 hours for weapons/firearm modifications and 6 hours for vehicle modifications. Apply all appropriate modifiers from the Build/Repair Table, p. 125, SR4. Once the modification process has started, it can be interrupted at any time and picked up again at a later time, unless special circumstances prohibit such action. Likewise, the object being modified might not be usable until
the modification is finished.
With any given gear item, you can only do one modification at a time. If a character wants to apply more than one modification to the same object, he has to make the modifications one after the other. He is allowed to choose the order in which he wants to apply the modifications, unless the modification description says otherwise.
As soon as a character has accumulated the required number of hits, the modification is successful. If, however, one of the rolls comes up as a critical glitch, the modification fails and needs to be restarted with a new set of materials. In extreme cases, depending largely on the type and extensiveness of the modification, the gamemaster may decide that not only was the
modification a failure, but that the object itself and maybe even some of the tools have been damaged in the process.
Some modifications require a character to possess an additional skill in order to be successful. When this is the case, the modification is handled with two Extended Tests, one based on the usual modification skill (see above) and the other based on the special skill. The character can freely choose the order in which the tests are rolled—he may even choose an alternating order. In order to successfully conclude the modification, he has to achieve a number of hits equal to half of the original threshold in both tests.
Every modification of a vehicle or firearm uses up one or more slots, and each such gear item can only hold a limited number of modifications, represented by a slot maximum. Vehicles have a slot maximum value of 4 or their Body Attribute, whichever is higher. Firearms have a slot maximum value of 6. At the gamemaster’s discretion, other gear may have slot maximums as well, though he will need to decide these values on his own.