I did this repair successfully. Very happy. My battery was bloated so it took significant persuading to get it out. I tried some pushing from the other side but didn't want to damage things as others have commented. So ultimately needle nose pliers to pull and a screwdriver inside to pry more room while pulling worked. I did puncture the batt... but it didn't explode into a fireball.
Someone mentioned trouble with the end caps. I made sure to mark the two screw holes on each side from step 3. It helped line them up for reassembly. I will do it again with my second flip4. Good luck. It's not impossible but definitely intermediate job.
