I lifted the body up 20mm this weekend to give myself a little more clearance between the rear bumper and the swing out spare. The car was never too noisy but is now even quieter and I think the reason was that the body was touching the chassis somewhere and sending chassis vibes into the cab. I am pleased.
The take away is that the body is meant to be completely isolated via rubber mounts from the chassis - for example the radiator - which sits on the chassis - is rubber mounted to the body, as are all the body to chassis mounts.
Makes me think of roof rack ladders that mount from bumper to rack....
I only lifted it 20mm and the issues were slight: I extended the diff lock levers, fiddled the diesel filler neck a bit, still need to make some lower brackets for the radiator. For now they still are secure. transfer case lever is still fine as I already have a small extender in there.
I dont know how it happened but the spare wheel mount was touching the rear bumper in spite of me being quite certain of the measurements (taken off the cabrio) before i drilled the mount holes