Hi ace2727 i have a GPS 1.9 and it has a factory fit alarm that works off of the key. The stickers in the window say "protected by fiat alarm lineaccessori".
It does seem pretty good, if not a bit too sensative. The 1st day i got the car the alarm it went off 5 times, but not much since.
Not sure how much it cost as i didnt buy the car new.