What HID replacements to get for best vision?

Already patented, its called Adaptive Frontal-lighting System, AFS for short, see: http://www.hella.com/produktion/Hel...AutoIndustry/Light/TIScheinwerfe_GB_TT_18.pdf

Regarding the tinted windows, dump them, they will only get you in trouble at night because its already hard enough to see with regular windows.

 

What I like about 4300K is its more true to the "sun" and so colors are more accurate at night 'as if in the sun" than the higher K units.
The lower the K, the more actual lumen's are transmitted "per watt" but some feel the higher Kelvin bulbs "look" brighter.

I think some of this phenomenon is due to the cones in our eyes and our brain programming.

If we see a frequency thats normally associated with very bright light, it will often look brighter "we think".

Look at an led.. it "looks" very bright, but has little power to actually reach into the darkness any great distances, hit an object and then accurate reflect the light back for your eye to see.

The 4300 Kelvin will look whiter when looking in your review mirror at surrounding cars.

I guess its what your preference is... I got the 6000K once and I actually prefer seeing color more accurately..... trees, grass, the road.. objects in the road etc.... I think they are safer for accurately determining whats on the road.... Our brains are used to dealing with this frequency in the daylight.

I doubt you will ever see 6000K on trains or planes because of this characteristic of light.

Just My opinion.