During restoration of my '69 911, I have removed the rocker panels (rust!)for replacement. Can someone tell me the purpose of the round, flexible, "tubes" that the heating ducts pass through in the rocker area? Are they to dampen noise/vibration? Or perhaps to help retain some heat...once they warm up? <img border="0" alt="[ouch]" title="" src="graemlins/c.gif" />