Knew you would say this. It bothers me, too. I'm going with the thought that he meant "a piece of mind" as in something like "I'll give you a piece of my mind", like to have thoughts, rather than a clam, peaceful mind. So, I think he wants to say that he will change in order to have better thoughts. But if you still don't see this as making sense, oh well. I think it does.
It 100% does not make sense in any form of English, take it from a guy who has a Masters degree in English
He just meant "peace of mind" instead. His English ain't perfect, not the first time he's done it. Oh well
btw thanks for posting the lyrics en-loss. They're not as impressive as I first thought really. Better than ASOP but worse than CC. They're all rather wishy-washy and basic, again. Anders really could do with going back to the older albums and remembering what it was like to write good lyrics. These aren't terrible but they're so... hollow.