sql query help - how to exclude from user post-count comments & nodes with a particular taxonomy term

I've been using this block snippet for a while from here

<?php
  echo "<h3>Most active in the last week</h3>";
  $active_week_result = db_query_range("


SELECT uid, SUM(count) sum FROM
(
 (SELECT u.uid, COUNT(DISTINCT(n.nid)) count
 FROM {users} u
 LEFT JOIN {node} n ON u.uid = n.uid
 WHERE u.uid <> 0
   AND n.type = 'forum'
   AND n.created > %d - (7 * 24 * 60 * 60)
    
GROUP BY u.uid) 

 UNION
  
  (SELECT u.uid, COUNT(DISTINCT(c.cid)) count
  FROM {users} u
  LEFT JOIN {comments} c ON c.uid = u.uid
  WHERE u.uid  <> 0
    AND c.timestamp > %d - (7 * 24 * 60 * 60)
    
  GROUP BY u.uid)
 
 ORDER BY count DESC
) 
as x
GROUP BY uid
ORDER BY count DESC

", time(), time(),
0, 10); //Change the second number in this line to the number of results you want to get.
  $list = array();
  while($row = db_fetch_array($active_week_result)){
    $account = user_load(array('uid' => $row['uid']));
    $list[] = theme('username', $account) ." (". $row['sum'] .")";
  }
  print theme('item_list', $list);
?>

What it does is count nodes and comments per user, sort highest to lowest and display the top ten... in the last 7 days.

What I want it to do is count all nodes and comments except those associated with taxonomy term with tid of 199 (which happens to be a hidden forum).

I've attempted to do another SELECT within the SELECTs but have very little knowledge of how to write proper SQL, so it didn't work.
Nodes are related to taxonomy terms in "term node" (nid and tid columns).
I guess comments are related to taxonomy terms only distantly by their relationship to nodes.

So how can this query be changed to exclude nodes associated w/tid 199... and then also how to exclude comments associated with those nodes?