yes i have nice yellow Billet 4s on my VR6
i absolutely love them, far superior to OE brakes & awesome performance
i chose HiSpec as they were the only 4 pots i could get which would fit under the 15" speedlines
as far as i know there are several reputable workshops that recommend HiSpecs for corrado's - pretty sure ive seen John Mitchell Racing fitting them to customers cars
you can give them you full wheel spec & they will confirm if you can run 312's or tell you the max disc size for your setup
i found them to be very helpful but i would say to not use their spacers if you need them as the cheap ones they did me were not hubcentric