My girlfriend is running an Yokohama Avid Engivor (205/60/16) with 11.5" shocks and she only done the nut cage mod and doesn't have any rubbing problems but the bike does sit more upright on the side stand to the point she has to really make sure where she parks or the bike could go over with very little effort. I am not sure what running a 55 series tire would do to the stance but I am sure it would sit even more upright. the combination will also decrease the lean angle of the bike so you will drag pegs sooner.
As for the shocks, they are an
E-Bay find...reasonably priced...shocks. They have the 5 position for pre-sets instead of the progressive settings of the Progressive shocks. The only thing is...they don't seem to fit the final drive very well as there is a bit of side to side looseness in them. They seem to meet her needs very well. Her bike is set up solo and she rarely carries more than her saddlebags will hold.
Joe