Larger turbo on stock ECU will run rich
To protect the engine.
No chance of getting 280kw with just a computer.
As zebra said, chances are that it's got stock injectors, fuel pump and AFM because its the stock computer.
So max with those parts and a tune is around 210-220 but with a larger turbo its going to be a laggy 210-220 I would guess.
So start planning what you want and we can help try come up with what you will need.