Definitely won't damage anything driving with the vct plug unplugged.
I wouldn't think cams are the best use of money at this stage.
Cam gears perhaps, but the dyno time to dial them in might not be worth it.
I thought the z32 ecu needs an additional window switch to control the vct.
Mat only very recently added vct control to the z32 ecu's. I would look into whet you actually have it or not.
A quick way would be disconnect vct plug and go for a drive. If it's the same you need to get it working.
Contact matt at nistune about the update.