Do you think it will have a visible increase in e.g. throw and how about the (shorter) runtime on 4A?
Difference in throw was visible, runtime as I don't use flashlights for that long is not that important, you can always switch to lower mode :)
Interesting... We want beamshot comparison or it did not happen... 
Hahhaha, think as you want :) I don't have to proove anything to anyone :) I had to remove driver as it overheated and turned off itself after 20-30seconds of use max, I don't want to put it all in heatsing grease as I did in Skyray 3t6-850 (and it works with 30W power for at least 5 minutes, without grease it did as above mentioned one), but they write at KAI that this driver is rather for 2 or more leds for some reason. Now I wait for SST-50 driver from DX which is claimed 4A into led, would be great if it works, I can do some beamshots then, I will not solder it now again for your curiosity :) But belive me, 15000 lux difference (1m front)is visible in night at throw :) But it is not something really big. Nothing now is, new led has to be announced... ;)
Is this flashlight identical (head/reflector diammeter) to SkyRAY STL-V2 or to Uniquefire V2 (UF has little smaller head diammeter, smaller reflector, and significantly less output)
Very grateful for the reply.
Yep. I believe the output to be the same on each. Mine is actually brighter than my M3X on a wall.
SkyRay STL-V2 and FandyFire STL-V6 are the same, just different brand names on them.
The Uniquefire I don't believe to be the same output or driven as hard. I have it as well. But it's still a good light.
Yes, I was wondering about that, because people were talking that about UF V2 too - thats a clone, very similar but different flashlight - it has smaller head diammeter and reflector diammeter, and Im not at all satisfied with output
(Also, dont order SkyRay STL-V2 from Dinodirect because you'll most probably get Uniquefire V2!... different flashlight).
And also I see ther were 2 similar kinds of Fandyfires on dx, (right now I cant find other), wich makes things more complicated.
Im looking for lowest price SKyRay-STL (or identical) flashlight, I know manafont has it, but its few dolars more expensive.
Have you measured their head and reflector diammeter?? (Uniquefire and that STL-V6 Fandyfire??) I measured Uniquefire diammeters and they are smaller than SkyRay's.
The Uniquefire I believe is smaller diameter bezel.
Buy the FandyFire STL-V6 for like $45 from Deal Xtreme. You will be tickled.