I did this same mod with the P4. It seemed to be about the only LED with the right footprint.
Works great, but the operation is more delicate than the thread suggests, at least for my fingers. You're working down inside the unit a bit –– remember that "Operation" game when you were a kid? Not much work area. Three comments to add to the instructions:
1. Popping the Luxeon out was a bitch. I almost gave up a few times, but eventually it gave. Just try to find the right kind of tool to get under and pop it out after desoldering the connections.
2. Go lightly on the thermal epoxy on the back of the new LED. Too thick on the coating will make it hard to seat it flush in the well for the LED. You'll see when you pop the old one out that there is a depression it sits in.
3. Mine sat up a little high when I was done b/c of the epoxy coat. When I tightened the bezel, I think it bottomed on the circuit board and shorted the LED connections. It was fine until I screwed it on, but when I tightened it, light wouldn't work. Fixed that problem by lightly filing the base of the reflector, which is thick aluminum and there's plenty of material to work with. Took about 10 seconds.
Since then, works like a champ. Brighter than the original for sure, but not orders of magnitude better.
Hope this helps.