How much is involved changing drums to calipers anyone done it
It would throw the whole balance of the braking system out and you would probably end up coming to a halt with the back wheels locked and sliding any time you put anything but the lightest pressure on the pedal in the wet.
Assuming you are talking about the rear drums on a Marea, why would you want to? It would throw the whole balance of the braking system out and you would probably end up coming to a halt with the back wheels locked and sliding any time you put anything but the lightest pressure on the pedal in the wet.
If another model of the same car has discs all round then it would be ok to change them but you would need to make sure that the whole system including any compensator valves etc were changed over otherwise the system will be too rear brake biased. I am still not sure why you would want to do it except for the look, most of the braking effort on all cars is from the front because the weight of the car moves to the front when you brake and the back goes light. Personally I would prefer to spend my money and time making sure what was there was working properly. We have to assume Fiat know something about building cars and usually get things like the braking systems about right.