there has been a few talks on PCCB and it seems a pointless buy imo on this car.
on the older car you only got small brakes so upgrading to PCCB was a good thing if you wanted better brakes.
On the GT4 it has the same calipers, with the advantage to use what pad you like and changing out cheaper iron disks once worn.
It also allows you to fit 18" or 19" wheels for track like the race car (which has even smaller brakes and does fine) the 420CCB disk does not allow a smaller wheel fitment.
IT has also come out that you get more down force with smaller disks , which is news on me but good news all the same and again the race car has smaller disks !
One thing the GT4 don't need is better brakes, the iron 380mm 6 pots do the job and then some.
so a "definitely recommend" is not what I would say as all it leaves you with is a £5k cost up front or 8% of the cars value, a set of brakes you really have to look after ie Major cool down laps 2 not 1 and major replacement costs, added to which to be safe Porsche recommend changing PCCB pads 1/2 worn and PCCB pads are also very expensive. You also have to be on best garage duty when taking a wheel off to avoid chipping the disk, again not that easy as the wheel to disk gap is small.
I think PCCB are just a hassle all round only fit for a road only car if you plan to keep it 70k miles as wear for the road only will be minimum.
As the GT4 is based on a drive to track and have fun car my advice would be to say "I can definitely NOT recommend the pccbs" unless you want the cool look and less dust