While replacing my iPhone 5c battery, I tore the upper component cable. (This was before I found iFixit's guides.) Because the battery I ordered on Amazon was total shite, I ended up putting the original battery back in, and one of iFixit's batteries is being shipped to me now.
Whew! It went pretty smoothly, but it took just under 2 hours total, including getting my space ready, containers for parts/screws, and labeling parts/screws religiously. This is NOT a simple repair, but it is easily doable if you go slowly and follow the directions to the letter.
This is actually my second attempt at repairing the upper component cable. The first time, I used a cheaper cable from Amazon, but it didn't come with attached brackets. Naturally, I didn't get them quite right, and neither the power button nor the mute button worked.
With the iFixit cable, the repair was quicker, and my power button now works! The mute button is stuck on "mute" -- I'm sure I could open the phone again and adjust it, but I always keep my phone on vibrate anyway.
MAKE SURE that the camera clip, volume/mute clip, and wifi antenna clip are not under the logic board before you start screwing it down.