"However the GT2 steel brake fits the GT3 perfectly, front and rear wheel carrier are the same as on the GT2. Important is only the rim one uses on the GT3 but I already saw a GT3 with the steel brake and the original Sport Design wheels with slight modifications.
Everything is possible but the question is if Porsche approves it or not"

What's the difference between GT3 steel and GT2 steel if any?

What's the difference between GT3 PCCB and GT2 PCCB if any?

how do the steel and PCCB differ?

What parts are needed to go from a car with original steel setup to PCCB and what is the cost?

What parts are needed to convert a car with original PCCB to steel and what is the cost?