Go the G4! i have em front, 8 pot 356mm and rear 6 pot, 356mm now its now very very good under brakes. Enough to give the GT3's a bath and yes i know their chinese, but do they stop. And fronts have over 3000kms of pure track work on them.
Next is the pedal box as they is quite some movement in the pedal now and with some adjustable bais to the rear its going to be sweet.