Try reaching your arm back there and tell us of there's enough room to work around. I know I would have to take it off in my GR, I'm not sure exactly where the gromit is in comparison to the GD, but if it is in roughly the same place, it would be a major PITA to work back there. It would be easier to take it off. A top mount should only take a few minutes to take off and put back on. It will free up a ton of space in that area. I would save yourself the headache and just remove it. You can reuse the bpv gasket too.