Don't worry about the ECU. It is similar with the 2.0TS unit. Actually i am now driving my tuned QV with ECU from 1.6TS. So no problems. I think that the swap will be very clear and easy. even your gearbox will fit without problems to 2,0TS engine block. But my question is, what do you expect fro mthis swap? Is this 147 will be only for daily use , or you will participate some trackday events? You will notice a high power gain, but after 4-5 days you will start to wondering..."Ohhh there is a difference, but not so negligible.."
So my suggestion is to avoid this 2.0Ts and start looking for a 2.0 16V Turbo from FIAT Coupe!! The Lampredi engine is a trully masterpiece and is 99% the same as that one in Lancia Delta Integrale Evo's. The only difference is the ECU, because Lancia use Magnetti Marelli units. This engine is sooo awesome, even stock it gains 200bhp, great fuel economy when drive it normally and sooo much performance potential. And they do not cost much then the 2.0TS, which i really do not like so much! Better choice then the 2.0TS!
You are right, the one is a Natural Aspirated engine and the other is Turbo engine. But with my racing experience, to start build a NA car instead of Turbo powered one is just a big wste of money guys!!! We are now in the Turbo era, where for less investments you can achieve huge difference in performance and power gains from one engine. And the feeling is different, everybody loves the "Whooopssss" sound when you accelerate or shift gears.
Its your choice mate, but my suggestion is to start looking for a 2.0 16V Turbo from FIAT!
The 2.0TS will feet absolutely without problems to your engine bay, but the power gains are negligible and you wil lbe disapointed after some time