Bought the kit from iFixit and just completed this! Keeping track of all the screws was tough (I used an old ice tray to keep track).

But other than that the process of removing the old battery was the most difficult. The instructions call out the plate behind the battery protecting the mousepad, but a picture or some sort of diagram would have been helpful. Bent him slightly, but nothing majorly damaged.

The only other super difficult part was cleaning/scrapping off the old adhesive. I literally got a razor blade to help me scrape off the old adhesive, finger nails still sore from this part!