I know a lot of people have come across an issue with high crankcase pressure for one reason or the other.
but what i'm wondering is, how would this affect the car. other than popping the dipstick or hurting valve seals, or finding another way for pressure to escape.
can it hurt perfomance or driveability of the car in any way?

I do not have crankcase issues, I had but sorted it out. but just curiosity brought me to ask.

 

I'd assume it at affects oil drainage back to the pan, forces oil into places you don't want it go, which could affect emissions, damage sensors, and generally gum stuff up.
I don't know the science, seeing how I've never had to deal with it. I'm just picturing it in my head.
Seems like it would be a while lotta bad.

 

I had crankcase pressure issues for a little bit and biggest downside was popping like every hard-to-get-to seal. They all began leaking prematurely. That alone is an enormous pain in the ***. Definitely not ideal.