Just use the original loom and coils, the modern coil pack is the same principal as 16i coils they are just 2 coils in the same lump of plastic , wiring wise they share a live and have a negative signal from the ecu,
I also used to keep a coil pack off a focus as a back up in case one of the 16i coils failed, I made up an adaptor lead to go from the 16i loom to a 3 pin plug that fits the coil packs