I purchased both the liberation kit and a new iPhone 4 battery. Well because I was seeing significant drain on mine ever since the iOS 5.0.1 update. I figured 30 bucks is better than having to send my phone away(no apple store for 2 hours).
Easy as pie! Take the back cover off... Pop in the new battery... snoop around at the inside of my favorite device... and voila... donezo!
Pretty straight forward if you ask me...