Great stuff, sound mods are hard to make and very valuable for AC as it's ACs only clear weak point.
About the brake squeal, David Perel (GT3 driver) had said to Kunos as feedback from ACC, that real driver hears aggressive grinding sound when braking, that is never heard in onboards and was missing from ACC... and Kunos will add that.
So maybe your version isn't that far from reality... and people just have wrong idea, when they base everything into onboards. It's tad loud maybe, but I would trust David Perel's word more than YouTube videos/sim racers