One of the reasons buyers opt for + one (or 2) conversions is that the larger wheel diameter fills the wheelwell and gives a better visual. There is only a few inches of space in our wheelwells so I would guess that any reduction in ride height is not for the faint of heart.. But years ago one of the first things US 911 owners did was lower their car, I seem to remember that the ride height was lower in Europe or it was just a common practice.