Performance issues and lag
Even with the changes, NPCs can still see you, they just won't attack, but that's better than it was before.
Only issue is heavy scientists. If you un-vanish and re-vanish they'll keep attacking you regardless.
The plugin needs to be updated. Lags while it's loaded.
Yeah, still having significant performance issues even after making the changes.
try out V1.0.2 and let me know how you go!
@Whispers88 no more lag, but doesnt vanish. Yes, we updated the new vanish.allow. 
At first , it vanished but now it doesnt work.
v1.0.5 fixed the null Ref errors but still gives

Calling 'VanishCommand' on 'Vanish v1.0.5' took average 2025ms

im Sure @Whispers88 is working to fix the problem we all must just take a deep breath and hope for the best .....
bytheway @Whispers88 thanks for the help last night +++++

Yes @Whispers88 thanks for all the hard work you are putting into this, it is very much appreciated by the community!

I am also still having issues with v1.0.5 unfortunately.

I can give you a bit of info it it helps: It worked fine for a while, I flew around the server in vanish and noclip. I teleported to a sleeping player's base... still no problems. Then I was standing outside (vanished), and an active player flew within visual range of me in a minicopter... that's when the same lag issue reappeared:

Calling 'OnNpcTarget' on 'Vanish v1.0.5' took average 7186ms
Calling 'OnNpcTarget' on 'Vanish v1.0.5' took average 7485ms
Calling 'OnEntityTakeDamage' on 'Vanish v1.0.5' took average 6085ms

Edit: Not sure what the "OnEntityTakeDamage" was about btw.