As someone fairly new here, I must admit that I am kind of sad at some of the responses you have received. Certainly not written in a kind and loving tone. I hope you didn't take offense.
I personally don't think there is anything wrong with the mortification of the flesh in and of itself. The metal cilice pales in comparison to the mortification that St. Mary of Egypt, the Stylites, and other "extreme" ascetics participated. However, I think you should be careful because extreme mortification can bring about extreme pride. I don't know about you, but fasting in body often brings about terrible pride for me. I can't imagine what kind of pride would manifest if I began more extreme mortification. All that to say, I think it is important to do these sorts of things for the right reasons. And also to put them into the hands of our spiritual fathers and mothers who know our weaknesses and know whether or not we are mature enough to take on more severe ascetic practices.
And mortification in and of itself does not save the soul. The mortification is to bring us into closer relationship to God. So the person who uses a metal cilice is not necessarily in any better position than the person who fasts in spirit and body every Wednesday and Friday of the year. With the help of your spiritual father, you two should be able to find the proper mortification for you.
And to be completely honest, I am newly converted and very young (24), so I hardly carry the wisdom to adequately address such a question.
Christ is Risen!