Why?
The 4x4 is already raised from the standard car and Fiat has spent a lot of time getting it to all work properly. Raising the suspension can lead to driveshaft problems, and these are horrendously expensive, and the rear suspension requires adjustment if disturbed. Raising it will throw out the angles, and who knows what it should then be?
If you NEED more clearance, you are probably using the wrong car.