Nodal Mechanics...is that a mod?
Yes, it is.
As to your wand question earlier, caps determine base discount, rods determine vis capacity. A scepter gains +10% vis discount and 50% extra storage, and all except one staff doubles the vis capacity (The exception is the Blood Magic related staff, which actually reduces the vis storage). Note I'm only including rods I know of and remeber the capacity of here.
Material - Wand Storage - Staff Storage - Scepter Storage
Amber - 10 - 20 - 15
Wood - 25 - 50 - 38
Greatwood - 50 - 100 - 75
Any Primal Rod (i.e. Blaze or reed), Transmutative - 75 - 150 - 113
Silverwood, Livingwood(FM), Dreamwood(FM) - 100 - 200 - 150
Infernal(FM), Tainted(FM) - 150 - 300 - 225
Primal - (No wand) - 250 - (no scepter) (This one is the one I'm most rusty on, I don't rember the exact number here, it might be higher)
Ichorium Wrapped Silverwood (KAMI) - 1000 - (No staff variant) - 1500