Yep, K070786 cross references to a 7PK2010. You can do cross reference checks on autopartoo.com or the belt manufacturers' websites usually have a cross ref search area. You can even put in OEM part numbers on some sites. The Bando site lists the wrong belt for our Z. I've emailed them but they didnt respond so dont follow the Bando site if anyone is searching for an OEM belt. Oddly enough, Bando makes the belts for Nissan...
I am just speculating that a 1990mm circumference belt will make the tensioner marks line up perfectly so feel free to try it and report back. Check to see if the store does no-fuss exchanges before purchasing
otherwise, 7PK2000 is what i've had on for over a year now with no issues.
As for the vibration issues, well let's just say it's a debatable topic. I've had the pulley for over a year now and engine still feels smooth. 3 oil changes and there has only been a tiny bit of metal powder on the magnetic plug but i am yet to do any UOA. To conclude, there's a risk with everything so weigh it up and make your own educated decisions