GTI 239 discs & pads fit straight on, the calipers & hubs are identical. IIRC the driver servo/MC setup is the same as the GTI one too!
It's only the 256/280 setup from the later 16v/G60 which had a different hubs, calipers & carriers, along with a bigger master cylinder.
BUT you have to fit GTI pads as well, because they are thinner to make up for the thicker vented disc
