Yes 18" - they also come in 11" rear if you can find them. I've seen these go for $1,000 - $2,000 with tires on eBay from dealerships selling take offs.

Watch out for some with snow tires since these are the snow tire rim on the 997.

57mm by far for the front. The rear, not as big of a deal. 65 in the front is ideal so the closer you get to that, the better. 50mm still works.

 

Thanks to everyone for the excellent advice. I picked up a set on Craigslist (specs shown in the initial post) and got them installed today. I love the 18s which replaced the puny 16s!!!

There is still some work to do. My original 16" Cups came with a 70" offset and factory spacer set-up. I had to discard the spacers on the new 58" set-up. However, my rear studs are now too long. The next project will be to shave down the studs, or change them to shorter studs, or look for a new set of 14x1.50 ball-seated lug nuts.

 

Nice wheels. Lose the silly old school locks. Don't cut the studs. Use open lug nuts ...

 

What he said ^^^^^

Then put the stock ones on top of the open lugs to keep that stockish looks, plus covers up the open stud and protects it from damage.

 

Looks awesome, I need to get a set of those.

 

These are the Carrera III wheels standard on the 997's. They are factory BBS original wheels 18X8 and 18X10. I run 225/40 and 285/30 Bridgestone Potenza RE050A Pole Position... a bit pricey buy insanely grippy on the street. In my opinion, running 265's on the rear is a bit wimpy. In this picture, the new suspension had not been installed yet and the car was still riding 'stock' which in my opinion 'again' is too high. Good luck in your search...

 

Here's a close up. Wow, these files are so large...sorry...they take up lots of room...

 

Here's a view from the back...once again...before lowering...