Looks like an XM-L based on the images in this thread
You’ll get more lumens from the efficacy gain but to get significantly more lumens you’ll need to modify the driver for more output, which might result in overheating if you overdo it.
Tests from here suggests XM-L will do roughly 600lm at 2A. SFT-40 test on the same link suggests it’ll do c.800 at the same current.