RE: ys175
No, it still uses the nuts, but the flanges do not get distorted, that is a big plus, so there is no leak there preventing for oil to be all over the place.
I will be trying the YS header vey soon, it has the same concept on the old Hatori, you can see it in Narukehobby's page, but the latest Hatori has been very good.
Regards
Alejandro