Guys

This may be a long shot but ....

I had a grinding/rubbing from the rear near side of my Cayman. Having had gearbox problems I thought this was the issue and called Porsche assist. The car was taken to the OPC and the fault ? was found to be a stone jammed in the caliper. You could not see it easily and it took the OPC almost a week to find !!

The grinding noise on my cay only happened badly when turning right, on left turns it could sometimes be heard faintly.

Hope this helps.

Bob