Computer wasn't cooling, fans made clicking noise.
Flawlessly. The repair guide is very well laid out. Follow the steps, be patient, and the process will work.
1.) If you're going to the trouble of replacing fan(s), check out the battery while you're at it. Replacing that as well isn't that much more work.
2.) I bought the ifixit toolkit (very well stocked!) meaning I had multiple spudgers. For the connectors that pop straight up (like the IO cable running across the right fan), using two spudgers simultaneously allows straight up action instead of a bit of shear from one-sided prying.