im lowered 40mm and it looks nice. any lower is a pain in the arse imo having to plan routes avoiding speed bumps etc, also although less of an issue you will have probs in areas like for example the overspill carpark at windsor castle is dirt and uneven with big holes in it, car park at chessington, etc.
I know those are situations most ppl wont find themselves in but it may be worth thinking about before going too low
