E30 Zone

Can I fit 215/40/17 rubber on to my 8" wheels (rear only)?

The cars currently lowered 60mm or so but I plan to raise this back up to around 30-40mm.

The arches need replacing to so I could always make some modifactions here if rubbing is going to be an issue.

Quick answer "yes"

yes but i think that 225 would be a better fit, not sure but i think that 215 would look a little streched, unless of course that is the look you are going for.