I scored one on either Amazon/Ebay for about $120 and put it in myself. I've put in various stereos so I have a clue but ain't a pro. It should have taken me 8 hrs the first time and by the third I would say 3 hours. However there were a couple of issues...it ended up taking about 20 hours!!!!
so the original instal took 8 hrs but it didn't work that included installing the LED which Ford will not install they just tape it under the dash, so the next day I double checked my connections = good the next day I triple checked my wires = good. I then pulled it out and reinstalled it with the wires in the open since I had no clue what to do. Now let me describe the alarm, you get a box with two different harness assemblies box is made by CodeAlarm for various mfrs you just change out harness and this chip. when I was checking for the 4th time I saw that although the instructions said "connect the blue wire with red stripe to the dome light" and "yellow wire to passenger door lock switch" when I looked at the colors on the harness they didn't go to the correct input pins....WTF so I ignored colors and hooked it up right. Well although it now did a few things it didn't work so I ended up calling Codealarm. Now let me say I fix stuff for a living and can talk to techs...he asked a bunch of questions which I had good answers for then he said "maybe you got a bad one" when I asked how to get a replacement he said "go to the parts department and swap it out." and was surprised I didn't work at a dealer. Well, I didn't buy from him so I was going to talk with the seller. However I noticed the chip which mounts on a plastic piece that snaps onto the alarm box was glued in the wrong position so it wouldn't line up with the slots...I bent an offset into the cover to get it to align and Voila it worked!!!
However I had wires running across the car and had to re-install it with hidden wires..yep 20 hrs.
Oh yeah, they talk about the i/r sensor but unless you have the dome light with the translucent piece in it you won't have that. It is a decent system that works off the factory alarm but I regret not getting it from the factory. If you need hints let me know.
2012 V6 traded in for a 2017 VW GTI.