Anyone know the standard piston diameters for the B5 S4 332 and 355 Stoptech kits?

[lookaught]

I've STFA extensively and googled, but apparently I suck at STFAing and googling.

I need these to compare to some Porsche calipers... though admittedly Im not sure if piston size alone can be directly compared with different caliper designs.

THanks!