Hmmm... I don't think it's okay to sing metallicca songs in church. they don't support christianity so why should their lyris be sung in church? In the youth band I play in (the leader used to be a shredder back in the 80's by the way so he knows every metallicca lick ever made) we do borrow licks from metallica and iron maiden and use them in songs. I do like metalicca and iron maiden but i believe most of their lyrics are not fit to be in church. Anyway our worship is loud and we really rock out the whole time. we just do our own versions of the songs, we don't try to make it exactly like the it is on the cd or anything. In fact we use distortion not an organ :D We play from our hearts and that's what worship music is all about.