cheapest, non-glare halogen-to-HID upgrade option?

a - Points 4 and 5 are dependent on the full headlamp assembly, not just the bulb. There are both really good and really bad headlights out there in every flavor - Halogen, HID, LED, etc. "Visibility" is really hard to define as a headlight projects light in most directions, and the ideal light from a headlight is different in different circumstances; the ideal light driving at 30mph on a back road is very different than the ideal light when on the interstate at 70mph.

b - No, not that I'm aware. Your cheapest solution would be to find a junkyard Prius and take the HID headlight assemblies and HID boxes, or buy used Prius HID assemblies, including the HID voltage step-up boxes (there's a better technical term, but I can't remember at the moment). I think new these run ~$250/headlight. The later model year gen 2's have the HID option available. I think this occurred on the "refresh", so 2007-2009 models would have them. Doing this for less than $200 is a stretch if you can't find a used/junkyard parts (and the HID option is not that common).

If bulb life is the primary concern, I would use long life bulbs. There's an engineering trade-off between bulb life and brightness however, so you'll sacrifice a bit of brightness and idea beam focus with the longer life bulbs.

If you live in a country that requires daytime running lights, a simpler mod might be to replace the bulbs in the front turn signal lights with dual color white/yellow LED lights. Having white LED lights there would likely meet your country's requirement.

 

What you’re asking is a tall order.

Fitting the whole system from a Prius that has HID is more complicated than “Goal 4: total DIY work time < 3 hours; DIY work must be on the low-medium scale of difficulty.”

Fitting a conversion kit that just goes in place of H4 bulb:

LED bulbs:
Finding a H4 LED bulb with more output than a good H4 bulb is hard. Most of LED bulbs have less light and don’t give the good light pattern. Bad light pattern reduces the useful light and blinds oncoming traffic. To get light output to the level of H4 bulb LED needs a lot of cooling and many LED bulbs don’t have that good of a cooling system. Some even have unreliable fan cooling. So I wouldn’t even be sure about the increased lifespan.

HID conversion kits:
Since H4 has both high and low beam in the same bulb the HID conversion kit bulbs have some moving element in them. Problems with those moving elements cause bad light pattern and reduces the lifespan of the system. Light output itself is a lot better than H4 if you use 35W system. Also most of these conversion kits have bulbs and ballasts in them that have short lifespan.

Here it would be illegal to use any of those HID or LED systems in headlight that’s just designed for H4. Markings on the “glass” of the headlight on (NON HID) Prius only allow you to use H4.

What I’m doing:
I have the Prius with H4 bulbs. And we have to use the headlights all the time as well. My Prius is also connected so that you always have headlights on.
I install good (high light output (but with normal wattage)) bulbs for winter when it’s dark and you really need light. Then when they burn out in spring/summer I install some cheap bulbs for summer. I have done this for many years I did it with my old car as well.

Would not be legal here. We can only use light assembly for the uses manufacturer has proofed it for. Proofed by markings in the headlight. And there’s no marking for separate Daytime Running Light in Prius headlight.

 

Shiraz,

You would get something like this:

JDM ASTAR New 7443 7444NA 3030 SMD White Yellow LED Switchback Turn Signal Light | eBay

You would also need a new wiring harness for it as the current one only has two wires for the turn signal. With the new harness, you would attach one wire to the parking light wire next to it to feed the white leds when just your running lights are on. Hope this makes sense and is of help.

 

Yes, a 7443 bulb wire harness. The stock one I believe is 7440 (or is at least compatible with every 7440 LED bulb I've put in my turn signal), which is for two wire, the 7443 is for a dual filament bulb (or in your case dual color LED) and is 3 wire. Example: 7443 Bulb Socket Brake Turn Signal Light Harness Wire LED Pig Tail Plug 7440 T20 | eBay

I would take a picture of the stock wire harness and compare it to ones online. I have no idea if the above one would fit to the headlight housing, but with a dremel, anything's possible

I also almost forgot - if you replace the turn signal bulb with a LED, you need to replace the turn signal relay as well, otherwise you'll end up with "hyper flash" (turn signal blinking too quickly). Here's the one I bought.

Replacing the relay is fairly easy, just need to take apart the bottom part of the driver's side dash and then feel around with the emergency flashers on until you feel the relay that clicks.

 

Going over your list. There Zero option!

 

I have the same issue as you. US car imported to Canada which had the DRL added by some yahoo at canadian tire most likely. All it is doing is running the low beam at around 70% power all the time and burning out headlights. First thing I did was pull the fuse to that DRL circuit, it was obvious and hanging under the hood by the jump start terminal. This will increase the life of the low beams and also after you put in fresh halogens, they will be brighter. (halogens dim with age) I've never been hassled about DRL by the police, if I did I wonder what they would say about the lack of DRL on their crown vics?

I have done a lot of headlight retrofits and I don't see an easy way to do it. Easiest way to get more light is add an offroad LED bar somewhere in the grill, wired up to a relay and a switch to the cabin. Since you are looking for light on country roads this is very easy to switch off when oncoming traffic is encountered.

 

an LED bar would be much brighter than highbeams if you get a decent one