It would be interesting to see what the factory spec of your car was using a VIN checker; my bet is that the car came with 18” 108 split rims and they became tatty due to corrosion so somebody put a cheaper set of 17”s on to tidy the car up for sale.
I can't recall seeing any Si Sport coupes or roadsters that came specced from factory on style 200 , or any other 17s for that matter :?
As rally Chris points out , worth tracking down your cars build sheet to show its original wheel spec