[limoncello]

I'm presently on 17" Porsche wheels with the standard size tires (205/50 and 255/40) - what size wheels and tires can you go to in a bolt-on mode, i.e. no changes, no fender scrub, no problems. Doubt I would go beyond 18" rims, but what about width? I see some interesting wheel/tire packages out there, but not sure what would fit and what wouldn't.
When do the spacers come into play? thanks for the patience -