I've got package #6 and have never been flashed because of the lights.
Maybe my auto-leveler is set correctly or that the drivers around here are
used to them (bluish cast). I think there is some adjustment screw on the
unit which sits on what normally be would be the rear differential.
Personally, I don't know if they are indeed brighter. I have some (non-HID)
higher wattage bulbs in one of my motorcycles and they are bright (80-110
watts verses the stock 55 watt ones). With those I can see "much" farther
than the Prius HID lamps and they really annoy other drivers on I-5 by the
number of flashes I get even on low beam. Fwiw, the blue color of the
spectrum isn't the best region for night vision, it would be better towards
the yellow/red portion of the spectrum (having had to read visual
densitometers of bygone era). Your eyes aren't normally sensitive to blue.
On the NAV, I'll never have another vehicle without one. I even installed
them on the motorcycles and previous car (Garmin units). Only problem with
the aftermarket installs is that you need to remove or hide them else they
are tempting for a thief. Very useful out of town in unfamiliar locations.