Fronts
no flares = 1" spacer
GT Flares = 2" spacer
Rears
no flare = a few
options extensivly modify the trailing arms, relocate the shocks inboard more and cut the trunk wall
or run a 993 or Boxster rear suspension setup
or build a custom SLA rear suspension
GT Flares (or similiar) = min 2" spacer to prevent rim/tire from hitting the inside structure of the car, of course flares will have to be implemented due to the width.
These figures and recommendations are IMHO and are not fact !!!!!