I am putting a mk1 Mondeo 2.0 Zetec Silvertop into a mK3 Fiesta Si with a 1.6 Zetec Silvertop.

I need to obtain an ECU for the 2.0 engine that works in harmony with the existing set up on the car, as far as I know its easy to get this wrong.

All advice on the correct ECU to obtain would be very welcome.