The motors arent the same, the Mazdaspeed3 engine has direct injection.
Plus, if you were to undertake the enormous and expensive task of swapping you'd have to get a cpu as well. And seeing how limited the tuning solutions for this car are right now, you'd be hard pressed to get it running properly without spending even more money at the dyno.
Just get a turbo kit. I used to own an SVT Focus, so i know the forced induction kits available are numerous and more affordable. Vortech's supercharger makes great power for the money, just as an example.
Think about it this way, in what other circumstance have you ever seen a motor from one company swapped into a car from another company? The only time i have is cars from the 60s. It's just never done, because its so cost prohibitive you might as well just buy the car with the engine already in it.