i have over 3000 kms of race or testing on mine and are good. only problem i had was dippy bloody mechanic ( me ) didnt do the bloody bleed nipple up tight, so lost brakes at 240 kph. Apart from that i have used one set of rotors and 6 sets of the green track pad in that time, never had to replace anything else.
I run the 356mm front and rear on a 1320 kg 500 hp R32 GTR race car
Why do people knock these when they have never tried them, granted they are not Alcon etc but a bloody sight better than stock sumito or brembo. This i know as i have brought the brembos, tried them used the stock sumito, and the G4 is miles in front.
I cant see how most people would believe that using 15 year old calipers which have possible never been serviced then a ISO 9002 companys new product which is larger in radius, lighter, greater pad surface area.