Good morning. The power windows on my 1991 Accord EX are becoming a bit balky. I can hear the motors laboring when I open and close the windows. My mechanic informs me that the door run channels should be replaced to eliminate the added friction from time and wear. The parts drawings suggest that there are some channel pieces down inside the door; do I replace these, or do I replace the rubber channel that runs around the window opening, or both? Any advice on this as a DIY job? Thanks -Mark