So i have been running 350mm discs with stock calipers on spacers.
I figured i should upgrade and now have a caliper set from a 997 turbo lying here.

I recon this is bolt on, but how about brake balance, do i need to change the master cylinder?

The rear calipers has what i believe is aluminium pistons, while the front have steel? with zircon pads, is this right or have i gotten a newer calipermodel for the rears?

 

​​​​​​No. The piston area is the same or smaller, depending on the calipers you use (steel or pccb).

 

Thanks, i believe these are from a steel disc car. The piston sizes are 28, 32 and 38mm

 

You should upgrade the rears too.

 

The rears are beeing swapped to, hence the question about them having aluminium pistons

 

I bought the 997 GT3 MkII version. These are right for the zirkon pistons.