Well if you get the chance to drive it and see if you prefer it, it sounds like a no lose situation to me mate.
I dont know what the specific power gains will be as ive never mapped that specific car.

With regards to where you will see gains, given the change in cams, its more likely you will see gains up top if anywhere but basically its a case of things can only be improved in areas where ford havent got them right in the first place.
If you always run your car on 98 RON, then the chances of seeing gains are higher. (as ford will have had to allow for 95 with their timing)