After a 300 mile run on Saturday in the Z, I was a couple of miles from home when i realised the car didnt feel right so stopped, this is what I found

 

 

4 of the studs had sheared, anyone else had this happen with spacers fitted?.

Looking at picture they don't look hubcentric if they are there's a very small ridge for the centre bore of the wheel to sit around .also are the factory studs recessed into the spacer if there proud wheel can have fitment problems unless there is recesses in the back face of the aftermarket wheels .

They are or 'were' before the hub flange was destroyed. You can see how uneven it is, it's clearly been damaged. Spacers should always come with special low-profile studs that sit flush or under the level of the hub face, but yes, very correct, if the wrong studs were fitted and the wheel wasn't flat against the hub.