Afew questions for you:-

why EFI on the S1 are you planning on going cossie management??

My mate has just converted his 90 spec escort and regrets it on the cost front, to get the power out of it now he will have to spend £800 on the stage 2 gear to get the power out of it thats on top of the cost of the parts to convert in the first place.

Parts he used:-

MK4 XR3I EFI loom and cut the connectors off a OFAB frst loom
Keep your standard pump or use an EFI XR3I Tank and pump
OFAB/C ECU
OFAB/C Map sensor
OFAB/C Edis module
Fuel co/pot
Conveter plate from MFI - EFI look on ebay
Inlet manifold off a Fiesta rs turbo as you need the ISCV on the right hand side of it.
Crank postion sensor fitted drill block or buy a kit from burton power or oddkidd creations
90 spec rocker cover
FRST charge carrier or run a long pipe to you exsisting pipe and use the plug on the top right

Why not keep the mfi and run 5th injector setup and a proper cam kit and decent setup.
Or better still save the money you would use to convert this and give jamsport a buzz they sell the gotech kit for your car and i think they sell it as a home build kit now for about £350ish and you run what ever injectors etc you want, comes with built in map sensor, edis etc..... and you can run it on a dizzy.