Will a 1.8 16v fit into a p reg 1.2?engine mounts an wiring?

i have a 1.2 p reg that i'm fitting a 1.8 16v into it an i want to know if the wiring will still be the same?i have the wiring loom and ecu for it but can i just plug it straight into it?an do i need to do anything with the engine mounts or can i just bolt them on an bolt in the engine?any help would be greatly appreciated!