You haven't experienced crap brakes until you've driven a Corrado or Golf VR6
288mm IIRC? The older generations weren't great!
The 312s aren't terrible, but are easily cooked, without question. My current setup (latest generation R/S3/PP/Clubsport with 340s and 60mm piston) isn't massively more powerful in terms of stopping ability, but do seem to resist fade much better.
Don't get me wrong, they do stop the car better than the standard setup but the main reason I upgraded was to combat sudden and severe fade. They certainly tick that box, and that's with OEM discs and pads, nothing fancy.