I've just swapped my sony xplod out of my old Alfa into the punto mk2 (radio/tape deck)
1st .. don't buy the of the bay as stated like i did. The release pins were handy but the new facia was a very poor fit and took some extra work to get the side claws to snap in the 2 holes on the dash. iso leads were incorrect.
2nd .. After seeing i couldn't conect the cars harness to the sony, checked the xplod old box and in there was the correct wiring harness that i didn't need when fitting it to my Alfa. Just connect the male to female iso's and then the connector to back of your sony (you will need an antenna adaptor unless you use the one from your pug). I like to switch my unit off myself and not with the ignition so can't help you on that.
hope this helps.