I did this on my 1100et , 1100et swinging arm (ali) standard, bandit 12 rear wheel , et carrier, 170 tyre, offset sprocket and 530 chain / rear sprocket,, dropped calliper down to bottom ( b6 calliper) , bespoke dog bone made up to act as calliper stay which goes from calliper up to lower shock mount. no frame mods required . not sure if gs frame is same as et but sure someone here can confirm that. pm if you wish will post a pic shortly.