Bought these second hand on facebook marketplace. They were black with genuine discs for £1200. Got them powdered gold by a local place and put the discs from my old wheels on. Front was 800g lighter than standard and rear 2.2kg. This was with bathroom scales so not the best accuracy, but I definitely noticed a big difference in the rear wheel when the tyres were off. Noticed the difference in riding just turning out of my street. It changes direction like a pushbike now and acceleration/braking is markedly improved. It's just more responsive in every way.
I’ve three sets on different bikes and yes they make a big difference, you’ll notice the difference in acceleration and braking as well, takes less to spin them and less to stop them and may need to adjust the suspension as well.