My personal belief is that the upgrade hierarchy follows the signal path. Upgrades at the earliest part of the chain give best results for the money spent. If you are already at the maximum level you intend to go with the source, then the preamp would be next, then the amp, then the speakers. In cabling, the earliest cables in the path will be first, then follow to the next ones, and finally speaker cables. If you feel that you are balanced with all your components and cables, but have one "sore thumb" that is holding everything else back, then you can attend to that first.
To address your specifics, if you feel that your AC power is still not good, then the power upgrade would come first. Then, I would go for the mod on the Wadia. Then mod your VAC. Then the cables. Then the Subwoofer.
My 2 cents.
To address your specifics, if you feel that your AC power is still not good, then the power upgrade would come first. Then, I would go for the mod on the Wadia. Then mod your VAC. Then the cables. Then the Subwoofer.
My 2 cents.