Ferdie:
 Anyhow I can only see three reasons why Porsche does not rate the Super Sport on the 997:

a. the tire is inappropriate

b. the rating is in the procedure to be released

c. there is a delay due to technical or organizational reasons.

On a sidenote, the current pdf listing available tire options does not list the Super Sport for the 991 as well, only the Goodyear and Pirelli.

A cynic might add a fourth reason:  to keep the N rating for the PSS uniquely on the 991 to enhance sales, at least for a year or two.     As Futch noted PAG does not feel a need to keep re-establishing N ratings for new tires on quite old Porsche models; perhaps we will see if their new approach to N ratings is to only do so for cars currently in production, essentially declaring any models immediately prior to the current ones to be "old".  


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2011 Range Rover Sport S/C,  2009 Porsche 911S