Hi. I wasn't able to replace it yet- lack of time
and..... COVID 19
so I was puffing like my Cupra whole last week
But it's a bad news what you observed
I will replace the whole intake for stock (even the filter). I'm not looking for a total solution (because of almost completely removed exhaust system) but maybe a slight improvement. If it doesn't
help maybe I will invest in PCV retrofit from MK8. It will be way cheaper and worth to try. After that it will be probably one solution- Valve steam seals. But for that repair I need to wait untill timing chain replacement, and it will be a while yet, due to it's perfect condition.