A UK source of XHP50.2 3v emitters would be good. I got my last two from Ali express. Shipping was pretty quick.
Do you mean that you have the led4power board? I’ve used a couple of those. I’m not really experienced in reflow either. But those boards do require a lot of heat, so a solder iron alone is definitely going to be just a frustration.
What I ended up doing is putting the board in the clamps of my helping hands, and pre-heating the bottom with a turbo lighter. Then I used my soldering iron to add a little solder to each LED pad. Then I put some fresh liquid flux on the LED pads, and added the LEDs. After that, I heated the board some more with the lighter underneath until I could see the LEDs settle into place. I was moving the lighter around under the board, so it was pretty evenly heated, except I kept it mostly under the LED pads, so they were just a bit hotter than the rest of the board.
After the LEDs were soldered down, I used some cotton swabs soaked with alcohol to clean the flux off the top of the board. I also alcohol cleaned the domes of the LEDs, since some BLF members have had LEDs burn up when they forgot to clean them after soldering.
EDIT: led4power has Luxeon MZ quad die 3V emitters, and he makes this claim:
The Luxeon MZ isn’t the king anymore.
Ah, okay. I guess he needs to update his listing information then. Anyway, if enough people committed to buying them, he might be talked into sourcing some 3 volt XHP-50.2 emitters. Then, members could buy them from him already reflowed on his board and no group buy needed. He currently has no CREE emitters listed on his site.
XHP35 is the way to go on the Q8, I love mine.
If you cant do 35hi’s then 50.2 is the way to go.
I would definitely be in for one.
In for one or two if neutral CCI.
Is the even a neutral 50.2?
Yes, but only down to 5400k.
I’ve actually been meaning to do a group buy of the XHP50.2+BLF Q8 upgrade kit, but I first need to ship every order in my own GBs, and find the time. 
What maximal lumen output can be expected with the upgrade kit - 4x XHP50.2 ?
Mine at turn on with VTC5A’s 16000+lm on my calibrated T/A Maukka 4” tube. YMMV…
With 20S 17000+lm
My X6 Copper 21700 30T with lens… 4800lm
X6 with out lens…. 5000+ lm
Would like to see what 4x30T’s would do… 
I would be in. Depending on price of course.
I will take one, hopefully it will be less than Q8 itself.
Kaidomain have the bare 6000K and 6500K LEDs, free shipping to the UK but takes a little while.
Thanks for this. But I much prefer neutral/warm tints (4000k is favourite), so even at 5400k it’s pushing it a bit.
KawiBoy - Have you modified or upgraded your Q8 in any other way to get those numbers? Other than the XHP50’s and spring bypasses I presume?
No not that I can remember Tinergy 18awg bypass’s on the springs, 18awg leads…
Remember you have to open the emitter holes in the reflector a bit…
I just chamfer the emitter holes to just fit around the emitter pad to keep it centered with out bang it around or use centering rings…
Here are some of my bit(s) I use… some use tapered reamers?
I might of changed the FET to an Infineon? I do that because of the cloned/fake/copied FET and 7135’s that are out there now… I only buy the important stuff from Arrow, Digikey or Mouser… I don’t remember having to do that on the Sofirn Q8…
Thanks KawiBoy!
I’d be in for a pair for sure. Have been looking to upgrade my q8 somehow.
How much will sustainable lumens increase with 3V 50.2? If I’m not wrong the original Q8 stabilises around 1500 lm.
I also wonder about the beam profile. With stock XPL HDs the Q8 has nice balanced beam with some usable throw. Wont XHP50’s change it into all out flooder?
Also did anyone consider swapping the stock LEDs with SST40 5000k? That would be a an interesting build.