[@Tearstone]
I expected this question, to be honest.
Yes, I know that it's a matter of perception and all that, which is exactly why I did not specify what [i]I[/i] feel is OP. I basically meant for the players to keep their character away from their own idea of what Over-Powered is. 
I do wish for this RP to have different power levels, to give a more "realistic" feel.
However, I also feel that it is my responsibility to react when the [i]other[/i] members of the RP reacts to someone's character as OP, in order for the roleplaying experience to be optimal for all parts involved.

I actually have a [i]lot[/i] of superhero/superhuman/mutant characters, because I've been making up personas for my action figures and dolls since before I could write. Some of them are OP as shit and some of them are so underpowered that they'd be killed within a few posts of battle. I have this one guy, who will also be making an appearance in this RP, that is pretty OP.

Jacques was originally based on [url=https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcS0yvsA73IH1nIBjKKq2DMWwj1rBjJ4jKU5yVGLTDbZX5BNln-S]this bloke[/url] while Ruben was originally based on a police officer figure that had a stunningly similar face. The Technopath, who has a real name and story and all, was actually based on a Peter Parker figure that I had, which I had no clue was a Peter Parker figure, 'cause I was five and the comics we had were in English.

Aside from the fact that my characters are based on action figures, I hope that it cleared up your question. If not, PM me and I'll explain it better.

[@Drake Baku]
I'll toss you a PM in a little while.