My quad arrives today and I'm already thinking about upgrading the RAM. I've never done it before but it seems fairly easy from YouTube videos. Here's my question though - will I be adding or replacing RAM? Am I adding two additional 2gb sticks to the two already in there, or am I swapping out two 2gb sticks for two 4gb sticks? Also, if anyone could point me to a reliable link for good cheap Mac RAM online I'd appreciate it! Thanks from a Mac n00b!