very few people can live map or write maps for the EFI management used with fiesta turbo lumps only people who spring to mind are Stu at MSD and Amhed at Grove.
These would be the people to ask but I expect your talking 300 quid upwards.

I would not focus on 200 bhp as im a great believer that many of these so called 200 bhp cars do not actually make that power. 180-190 bhp makes for a very quick and enjoyable car.