Change Metabox Title

The “Right way” to do this is hooking to the ‘add_meta_boxes’ action, like so:

add_action('add_meta_boxes', 'my_metabox_titles', 10, 2);
function my_metabox_titles($post_type, $post) {
    global $wp_meta_boxes; // array of defined metaboxes
    // cycle through the array, change the titles you want
}