They are the same offsets as the 18” Caymans I have put on my 03 S.
The fit for the rear is perfect I think. For the front I have 7mm spacers to install but they fit without them with no rubbing on the inside strut. I want the spacer to push them out a little. 10mm would be ideal as I want to keep the staggered track. No need for spacers on the rear I think but you could fit some if you wanted a wider look.
They fill the arches much better and the view from the rear is more purposeful. Very pleased with them and will keep the 17” for track use with a more track orientated tyre.
Not sure why tire sizes you have but with the 18’s and the wider tires there is a lot more grip so for our wet twisty Irish roads the extra security is nice.
Sent from my iPhone using Tapatalk Pro