ATF versus G60 versus Brembo piston sizes.

[YBK]

Most of 200q20v have had front replaced from ATE (UFO) to G60 and some even took Boxter S or Carrera 4 brakes without changing master cylinder.

I am wondering if anyone has piston sizes for the above. I measured 40mm in G60 which means 5027 mm square of effective surface per caliper.

What about ATE and different Brembos? Does anyone has any disassembled or has an old or new repair kit handy to measure pston diameter?