G'day mate, interesting on the 'hum' problem. I've not noticed that issue with any of the three Shure M97xE's, although I do get a 'burst' of hum sometimes when I either remove or insert the stylus for cleaning etc.
Is your stylus fully inserted? I presume that it is. Does your turntable have a separate 'ground' wire connected to the preamp earth terminal?
Also have you used insulating washers when you mounted the cartridge in the headshell? This is an interesting one as generally these washers aren't needed, however on one occasion I definitely needed them to stop a very bad (and loud) hum loop. Every set up tends to be different!
Also you did have any issues getting the overhang set up correctly? Some guidelines are in here:
http://www.mds975.co.uk/Content/vinyl07.html Regards, Felix aka catman.