flat out

Just took the rst s2 project for it's first run up and down the street and it's realy sluggish. iv put a new old engine in it out of a rotten s2.
the engine in the rotten s2 seamed te be fine but couldn't drive it as the clutch was slipping it's nuts off.
What could make it so sluggish the thing is i can't just take it up and down the street as it has no tax or mot yet.
im not sure if the turbo is fluffed as the one i put back on was off the old engine and the guy before me sead the oil return split open on him one day and there was oil every were.
I have another one that i think is good so i will be trying that if you think it's worth trying.
I have a adjustable boost valve on it and im not sure if it's full open or shut i only thought of it when i got in but ether way that shouldn't make it as slow as a 1.2 should it?
plus the old ecu's are still on there, i will be trying them tomorrow i should of changed them but when parked up it seemed to rev up alright.
The thing is iv had a tit full know iv the car for over a year as a project and it's starting to do my head in now. any suggestions would be great THE END
(FUCKING FORDS)
thanks for looking