It all depends what compression you have. I'm not saying that it will blow up. But there is a good chance that it will start to sepereate and can later begin to rub on the case sending metal pieces through your engine and ruining everything. I would serously suggest you get it done. But obvously you dont have to. It's basicly a $80 security policy.

As for them milled head its an awsome mod. For the money may be the best. I went from 116 to 140.