Phipsy

I have a 1.8 focus with a st170 engine fitted, It is still currently running on the 1.8 loom and ecu, After looking at both looms i have noticed there is one plug different which goes to the under bonnet fuse box, The 1.8 has 2 wires and the st loom has 3 wires, Will i need to change the fuse box to overcome this problem?

Also if i do change the fuse box will i find myself having to change something else along with it?

I have also been told i can use a shift light to control the VVT, Does anyone know if this is 100% possible and safe?

Any help is much appreciated.