Berjar

I have a set on my 991 and Surface tranforms confirmed thay would transfer if i got a 992.

GT3 Nut

This is incorrect. The rear rotors will work on either car but the fronts are different.
You may want to ask them the question again.
I have a set of both and both cars so I know this for a fact.
The offset on the front hat is different. and the shape of the hat is also different.
The 991 rotors will work on a GT4RS though.

Also keep in mind the rear rotors are 400mm not 390 like the PCCB. Iron rears are 380mm.
So either way you will need to use their spacer for the rear calipers in either case.

Hinz Motorsport

I am the US importer for Surface Transforms and help them identify new fitments frequently. Many fitments from previous models fit the next generation but there are variations so if it isn't already listed on STs site or mine, it may still be available. There are still quite a few fitments available that aren't listed, so if you don't see your application listed there is still a good chance we can get a kit together for you.

For a quick reference, here are a few fitments known to be compatible from 991 and 992 models:
991 Turbo ST rotors also fit 981/718 GT4, 991.2 Carrera models with PCCB, 992 Carrera models with PCCB, and 992 GTS/Turbo models with iron or PCCB.
991 GT3/GT2/RS ST rotors also fit 718 GT4RS models with either iron or PCCB brakes.

New fitments are out for 992 GT3/RS iron and PCCB models. To comply with European R90 regulations, they have to mimic factory sizes.
ST now has bespoke designs for 992 GT3/RS iron upgrade kits vs 992 GT3/RS PCCB replacement kits. Discs are intended to mimic factory sizes for new models going forward.

In short, it depends on which 991 model you have that will dictate compatibility with other models and factory-equipped brake systems. I am more than happy to sort it out for anyone who is interested.

mwar99

If the 991 fitment fits the GT4RS I would assume it would also probably work with a Spyder RS. Probably too early to get confirmation...