In my case, what happens is that the plastic pulley that carries the regulator wire breaks. I think its a really bad design, especially since I have now replaced two of them in just 50K miles on my 2000 SSEi. My previous 4 Bonnies never once had window regulator problems.
BTW, thanks for the tip re www.gmpartsdirect.com
. The best local price I could find for the window regulator unit was $260. I got the same GM part off the web site for $186 including shipping.