Jimmy,
   I fill the ends of my viper with great stuff foam insulation.  It seems to help cut down on the ringing sound when I brush against stuff carrying it in.  It would probably work on the hang on style as well if you like the summits.

maineac, are you filling all the tubes on the Summit stands and if so tell me exactly how you get access with the foam straw ? Drilling a few holes here and there ? Seems like the slats for the foot platform are the loudest ?