Per your PM request, here is some additional information and part numbers for the connectors.
BMW 'Socket Contact ELO': 61-13-8-364-842. 6 required (1 each +/- at the seat connectors, two + at the fusebox connector). The plugs that receive the connectors are physically different at the fusebox and the seats, but this same contact solidly 'clicks in' to both.
BMW 'Bushing Contact' 61-13-0-006-663. 1 required (K bus connector on the driver seat). This contact pushes in to the seat connector plug the same as the power contacts, but has a pigtail wire already attached.
For the ground/earth wiring I attached a generic 'ring' connector, that fit the bolt attaching the ground junction fan connectors to the sheet metal under the kick panels.
The K Bus wire is for the seat memory, and connects to the 'body bus' that runs throughout the car for communication between various components. They are little white wires with red and yellow stripes (WS/RT/GE in the wiring diagrams). For the driver seat, this allow you to have different memory settings tied to different driver keys, for example. The car programming does need to be changed to mark this feature as active.
I used the online WDS (wiring diagrams) to track down which wires connected where - it identifies the plugs, pin numbers used, wiring gauge and colours, fuse circuits, etc. It's located here:
http://wds.spaghetticoder.org/en/