Most of the Kits avaliable are not exactly plug and play. They do require a little wiring knowledge. The days of plug and play are gone for the Mustang. I should know I added the pony grill to my 06. I didn't use an aftermarket kit. I used the factory wiring. Installing the switch, fuse, relay, grill, and wiring harness was the easy part. What was difficult is finding a dealer that knows how to program the smart junction box to enable the fog lights. The lighting is computer controlled now, so just installing the hardware doesn't make them work. Now the aftermarket kits bypasses the computer, but you have to splice into the harness in a couple of places and pass through the firewall (at leaset on the Ford Kit). For those wanting to upgrade from the pony grill to the GT you will need to change the connectors on the harness. they use different bulbs.