Thats probably because at that sort of power 200 - 240, is about the limit you can get from Probably the turbo (depending on what you have), managment (or fueling) and a few other factors, so to go for more a change of turbo or turbo spec and managment would probably be in order and that really does change the way the car drives, it would go from a punchy feel to no doubt a rather lazy feel.

My mates got what i think is an excellent conversion, its a complete NMS engine build and runs a 5th injector for the extra fueling, without the need for cosworth management and it is running in the region of 230 - 250bhp and feels really good. Very punchy and quite savage, but still spins the wheels if not drivin correctly, which i think you will find with most escorts with 200+ ponies.

Andy