Eh I tryed to install an alarm with keyless entry myself. Got the alarm for like 75 figured that was cheaper then Ford putting one in for like 300. Started the install thought things were fine was having issues with the lights blinking and was like screw it took everything off and the car ran like **** turns out i zaped the PCM. So much for cheaper DIY lol now i still gotta pay to put it on. Figure at least if a shop does it and messes it up they have to cover it no matter what.
Just plain Keyless is probably a lot easyer though i don't know
lol wasn't gonna say it and sound cheap but mine was a bulldog. Had a lot more then 6 wires lol. One of these days i'll find someone to hook it up for me
I put the Bulldog kit on my DD (Bravada), and it took me about an hour. Make sure you have a multimeter to start probing wires, and it goes fairly painlessly. I'd recommend soldering the wires, since it asks you to tap into some higher amp wires, and you don't want resistance burning up your priceless Mustang. The kit says to splice and tape if I recall correctly.