M30 head is a sealed unit? Is that the reason the reflector fell out when I opened mine?
I wouldn't modify anything there, if you put in another type of led, you need another driver, surely a better heatsink, bullshit...
If you want an SST-90, you'll be helped soon : K90 Intimidator, 2200 Lumen. Too strong? K50 then, SST50, 1.000 Lumen. For the rest there won't be a stronger M21, that's the K50.