I wouldn't spend $120 on that kit. Check out How-To: Fog light HID kit in 2011 Jeep Grand Cherokee (pic heavy)
used a 35w and a relay to avoid the power draw issue.
I thought about going with a retrofit cause I did a dual setup on my bike (dual bi-xenon with 2 halo's) but if I retrofit my fogs I would want to retrofit my headlamps too. Currently, I don't have the motivation to bake my housing but may get froggy down the line.
Not meaning to thread jack, but anyone have any idea how to bypass the computer so when I put my high beams on my foglights stay on too? I know the reason behind it, only supposed to have so many forward facing lights, but living in the sticks of Louisiana it really helps to have as many lumens on the road as possible.