Looked into this a little bit and it appears that Nexen makes 17, 18, and 20s - no 19s from what I could find. Will call a dealer tomorrow to confirm though.
From what I could gather from scanning some users comments, the tires are ok for everyday driving, but not for auto-x, DE, or track.
For n rating, I understand that it's best to use what Porsche recommends, to stay within warranty parameters, especially while still under factory or extended warranties.
Anyways, that's all, cheers
