piece of cake, first you remove the original headunit using a special Fiat tool, or by using feeler gauges (thin flexible metal strips available at motor factors for small money) to push the release levers on the side of the headunit. the unit should then pull straight out. disconnect the wires at the back.
Next you'll need an adaptor plate, Autoleads or Fiat dealer do them, as do nmerous other companies, this should clip straight into facia but may require some glue on the flat part at the bottom to stop vibrations. your new headunit will have standard leads and plugs at the back and should accept the fiat leads. Some headunits are longer than others and you may have to hack out some of the back of the opening to make it fit. screw your new headunit into the cage when you are happy that the adaptor plate will fit properly. you'll probably get a trim with your new headunit that'll fit in front of the adaptor, make sure this fits properly as well. there's probably a few more posts on this toopic. as it's a commmon question
Met Cognac 99 Brava 100 HSX,
