Tinting my windows made a big difference in the brightness of the interior of my car as a whole. Several shades darker now with the moonroof closed (duh)
The 8" lilliput has to be brighter than the 7", because there are way fewer complaints about it. As I said, I am impressed with mine. The mirror effect is simply a result of the dullness of the backlight. Its the same as it is with any glass, if there is light on the other side, you can see through. If there is more light on your side of the glass, or direct light, you see a reflection. That is why the spot up on the dashboard would not work for me, it crossed the line between more bright light on my side of the screen and the backlight's brightness.