A year later.....
18k miles, over 450 hours, hot Summer temps, about 1/3 night driving and no one ever flashed me.
So what might be considered wrong with the F3, a larger led die, makes it better.
I really like how the F3 really lights up the sides of the road and I can also see better down the road.
The F3 with its slightly larger emitter spreads out the hot spot just enough to put light where the halogen bulb is lacking.
The halogen bulb creates too much of a laser beam effect and does not illuminate the sides of the road very well.
Correct focus is what now makes the newer LEDs work in a Halogen reflector.
Now focus is a very important attribute that the Halogen bulb has over the LED or the HID.
The need for the LED to have the exact focus of the Halogen filament is a bit over blown.
The filament diameters are: Halogen 1.4 mm, LED 2.3 mm, HID 5 mm.
But the HID and LED have 4 times the raw Lumens of the Halogen bulb.
Doubling the the raw lumens on a Halogen bulb is not enough, besides it shortens its already short life.
The LED, with a better focus than the HID, can project better than the HID.
The handicap for us is the H4 system in the ST.
The ST reflector does a good job of spreading out the light.
The H4 low beam is not at the focus point so you do not get the throw that a dual headlight system will do anyway.
This is the tradeoff that is made in the H4 system to create the sharp cutoff that the H4 is famous for.
The difference of the halogen bulb being omnidirectional and the LED projects side to side is not a problem.
The LED is more efficient in a rectangular headlight and after all the beam pattern is horizontal anyway.
The arguments that a LED bulb will not work in a halogen reflector are no longer valid.
The bottom line is, on a dark country road, I can see more than the necessary 100 yards down the road on low beam with either the F2 or F3 design without glaring opposing traffic.
For the record.
The F2 and the F3 could improve focus with a little more wafer thinning.
The process that removes the excess backing and enables the chip manufactures to squeeze their chips into thinner packages.
This would impact yield but would also improve thermal performance and sharper focus.
This may not be necessary as the current crop of LED bulbs have sufficient focus to be equivalent to Halogen bulb.
I also put the F3 into other vehicles that have DOT reflector headlights that have a stronger hotspot.
These headlights also work very well with the F3 bulb and project further than the ST H4.
Just make sure that you carefully adjust the beam pattern with any upgrade.
If your headlights are old they should be cleaned and polished.
If they are really old you might be surprised that an OEM replacement headlight housing will make a huge improvement.
Opinion: the nb35 "six pack" LED would be good for high beam, the F2 "thin LED" would be good for the low beam and the F3 "in between" LED would be a good compromise. Here I am splitting hairs so take it for what it is worth.
The recent Cougar motors "flagship" bulb is an interesting cross over. It runs at the F2 power level and housing with the bigger F3 chip.
Projector headlights loose half the available light compared to a reflector headlight.
So you will want the highest power and most lumen LED for a projector headlight because of its reduced light output.
I added an update to the first post for new readers.