I usually don't drive the C8 in the rain, just because I don't enjoy driving it in the rain. But today I had no choice. Just drove 2 hours in constant drizzle. Highways, city streets, big vehicles around me. Lots of spray. Got home and the car, which is black, looked clean! And there was hardly any water on it. Two minutes with a small blower and what was there was now dry. The a$$ end is a bit dirty as it is prone to sucking up the dirt, but even that was mild. I was really expecting the black to show a lot, but the ceramic did its job in this instance. During the drive I hit the 800km break in point, and I have yet had to wash the car. Will do that tomorrow anyway.
I have driven my C3, C5 and now my C7 countless times in the rain over the past 40 years. 