When I bought my JK, I had an alarm installed. I drive with stuff I'd like to keep and the factory "alarm" is crap. When I added the alarm fob to my keychain I noticed that all the keys seemed huge in my pocket. The factory key was the main problem. Since I didn't need alarm buttons anymore, I googled replacement keys with the chip and found iKeyless
and bought 2 of the older style Chrysler keys, with the chips.
As long as you have both of the factory keys, you can program the new keys while sitting in the Jeep. Instructions are included and are also available on their site online. The replacement keys are much smaller and work perfectly.
The programming didn't work exactly as stated when it came to the chimes that I was listening for, but watching the security light gave me the clues I needed to complete the programming.
Cost was about $18 each, much cheaper than from the dealership. They wanted $60/key.