Hi, your standard brakes are 240mm discs. The Rs turbo series 2 ones are 260mm discs.
I am in the process to put series 2 brakes in my car, and is a cuestion of direct bolting calipers with guides and discs.
Also you can mount cosworth front brakes that are 283mm discs.
In this same forum there is a thread on how to mount them, and is very easy also.