First, the Impact is a fantastic gun. I'm getting ready to order my second Impact and upgrade the first with a Power Plenum. Accurate, and the rest.
My Impact is a .25. Next will be a .22. Which should you get? Depends on what you want to do with it.
First, does Italy have something like a 12 foot pound limit on guns without a firearms license? If so, and you don't have a license, .22 or .177. That's a whole different situation.
For long range shooting such as 100 yards, the .25 is a laser without wind. The .22 will do just fine at 100, but doesn't seem to buck the wind quite as well.
For hunting, what's the game? If small like squirrels up to rabbits, the .22 can do just fine.
Air might be an issue as well, the .22 is more economical and the pellets are cheaper. In the US, JSB pellet tins sell for about $18. the .22 is 500 pellets and the .25 tins hold 300, so a difference of 40% in cost.
If punching paper at 50 yards, a .22 will be a good gun all the way around.
Just depends on what you want to do.