Mk6 escort gearbox's have longer gear ratios, which means it will take longer to rev = more lag

What spec t3?? Get some pics of the turbo and down pipe, and try and read the housing sizes of the housings

As above wrong chip = wrong ignition curve and incorrect fueling which will cause it to be less responsive

If I was you I would swap out the ecu for the direct replacement ofam and speak to karlos g on here about mapping, and injectors

Then fit something like a series one rs turbo gearbox, it will pick up a lot faster than with the one you most likely have fitted