[Mauer08]

Like the existing GT3, the new 992 Carrera's will roll on a staggered wheel setup, with 20' wheels on the front and 21's on the rear. These combined with the wider front rack will allow for greater forces on the rear axel when accelerating out of a curve.

 

[Sp33dster]

The only real downside to a staggered setup is the inability to rotate your tires front to back to reduce wear. I doubt that many people plan on driving their 992 throughout the winter but I'd definitely go with a square setup there.

 

[992gt3]

In addition to the wheel setup mentioned so far I would like to see these wheels made from carbon fiber, reducing rotation mass in a driver focused car can only do good.

 

[Mauer08]

You can always go that route through aftermarket, but expect to pay a hefty premium on that kind of wheel set. Lightweight alloys should serve the same purpose just fine.