You can find this product under LED Backup Reverse Lights
1) Open the trunk of your vehicle and remove the plastic push pins that hold plastic trunk liner to the sheet metal.
2) Unclip the connector to the tail lamp assembly. This will allow you to move the plastic trunk liner away from the wall and give you more space to work with.
3) Using an 11mm wrench remove the (3) 11mm nuts from the studs that hold the tail lamp assembly to the vehicle.
4) Pull the light assembly away from the vehicle. You'll see (2) white connectors on each side of the vehicle. Those are the connectors that for reverse bulbs. Turn the connector counter clockwise and remove it from the housing.
5) Pull the stock 912/921 bulb out of the socket.
6) Install the 921 912 T15 LED bulb in the same fashion that you removed the stock bulb in. (make sure to test it to light up first)
7) Do this for the (2) white connectors on the drivers side and the (2) white connectors on the passenger side. Now that all of the LED's are installed in place of the stock bulb you're going to want to test them before reinstalling the light housing assembly back to the vehicle. Because LED's are polarity sensitive they must be installed the correct way in order for them to work.
With the key in the ignition turn the key to the on position but do not start the vehicle. Push in the clutch and put the car in reverse. Get out of the vehicle and go to the back of the car to see that all bulbs are working. If one bulb isn't lightning up remove it from the connector, rotate it and then put it back into the connector. The bulb should then light up. After checking that the (4) LED backup reverse light bulbs are lit you can now start reinstalling the light assemblies back onto the vehicle in the same fashion you removed them.
LED (left) vs. Stock (right)
8) You're done! Enjoy you new LED backup lights
Special thanks to Boostaddict from mustangforums dot com for providing us these pictures and instructions on the install guide.