how much of a task is it to swap the front brakes on my escort 1.8 si to big cosworth ones?

i bought the discs, calipers and new pads off a mate - they are off an escort cosworth, they are big too!

I'm looking to fit the brakes this weekend I just need 1 brake pad retaining clip and that's the works!

How much of a job is it to fit the brakes? do I need any adaptors or anything or will they go straight on?

Cheers in advance!