The solid bushing inserts in the convertible subframe aren't any different to the Delrin bushings used as a upgrade for the standard subframe. You won't notice any difference in "harshness" really. Unless you are extra sensitive to that sort of thing. I noticed no harness change in my 854 ...

I'd have to echo Chuck's thoughts. I didn't notice any significant additional NVH, though I haven't polybushed any other suspension components. If you can live with the current NVH then you'll be fine with the subframe conversion. In my experience, if you've just slapped lowering springs onto the st...