I know this is not the correct way and you should always edit the template but i just edited the core buddy press navigation function. You will see below the google link I added.
function bp_get_displayed_user_nav() {
global $bp;
foreach ( (array) $bp->bp_nav as $user_nav_item ) {
if ( empty( $user_nav_item['show_for_displayed_user'] ) && !bp_is_my_profile() )
continue;
$selected = '';
if ( bp_is_current_component( $user_nav_item['slug'] ) ) {
$selected = ' class="current selected"';
}
if ( bp_loggedin_user_domain() ) {
$link = str_replace( bp_loggedin_user_domain(), bp_displayed_user_domain(), $user_nav_item['link'] );
} else {
$link = trailingslashit( bp_displayed_user_domain() . $user_nav_item['link'] );
}
echo apply_filters_ref_array( 'bp_get_displayed_user_nav_' . $user_nav_item['css_id'], array( '<li id="' . $user_nav_item['css_id'] . '-personal-li" ' . $selected . '><a id="user-' . $user_nav_item['css_id'] . '" href="' . $link . '">' . $user_nav_item['name'] . '</a></li>', &$user_nav_item ) );
}
echo "<li id=\"css-personal-li\"><a href="http://www.google.com">Google</a></li>";
}