They used to say they had lots of people with the ability to protect sources back when they were just a few with no such ability. That's a nice start on integrity. Far as leaks, they posted a lot of them over time that people couldn't verify if they wanted to given lack of internal access. So, my claim on them wouldn't go as far as yours.

Define "lied". Wikileaks publishes material that other people give them. I'm not saying Wikileaks would alter documents, I'm saying the people giving the documents to Wikileaks would alter them, and then Wikileaks will do its job and publish them.