I managed to de-dome a couple of XP-G3 S5 2C's yesterday, & spent some time testing them in the same Courui D01 that I have used recently to test some other emitters.
The de-dome was relatively clean;
Unless I'm doing something completely wrong, there's no way these things are going to be the new 'throw king' in a reflector light.
Running the emitters at their peak output (~8 Amps), the highest reading I could get was 264k.
I de-domed & tested two emitters, one on a Maxtoch 32mm board, the other on a Noctigon 32mm. Both were within a few k of each other.
In comparison, the 'good' XP-G2 S4 2B netted 443k under the same test conditions.
Even the Oslon 3rd Gen managed 410k.
The question of die-size between the 'good' XP-G2 & XP-G3 has popped up a couple of times. Here's what I measured with my dial-calipers;
'Good' XP-G2; 0.0530"
XP-G3; 0.0555"
So it is slightly bigger. But the XPL is a lot bigger, & an XPL HI V3 punches out ~360k in the same host...
New Throw king? I don't think so. 
- edit to correct bin/tint of the XPG3.