I modded two with the Sandwich Shoppe uncut high power LED. One was natural, one was black.
The natural one was epoxied-in and required quite a bit of careful scraping around the periphery of the printed circuit board to remove. The black one did not have this epoxy, and pushing on the LED was sufficient.
Since this LED wasn't tapered (as many are not), it required opening the hole in the reflector a bit. You can also polish the reflector while you have it apart.
I've had experience with the BestHongKong ultra white LED and the JELED. Despite having their own strengths, I still feel the Sandwich Shoppe LED has the most consistent white color and a smooth beam.
Look at post #77 here for beamshots:
https://www.candlepowerforums.com/threads/135284&page=3&pp=30