Because the T3 turbo is much bigger than the Fiesta turbo you need to move the radiator away from the turbo otherwise the heat generated by the turbo can cause the water to boil in the rad at that point. All my radiators for the Fiesta have the option to move the rad aprox 25mm further forward or right up again the back of the bonnet catch arrangement.

If you’re using the original rad you may have to make some brackets to move this further forward.