I originally considered swapping a LH351D into mine, but decided not too. Pushing a LH351D at 6 amps is past it’s peak and well past it’s sweet spot.
It probably won’t be anything revolutionary, but I ordered some 3V XHP50.2 to try in my SP35. I’m curious in the impact on raw output (lumens) and to see if it runs any cooler in Turbo (depends on how the vF compares vs the SST40). We’ll see. I know the beam will be ugly but I can’t help playing around.