I just received two of Lambda's SMJLED PR2 for 2 cells. One went into my Rayovac Industrial 2D. Output appears to be more than the stock KPR102 and due to this light's faceted reflector and the installed height of the PR LED insert, the beam quality is excellent with a large round spill and a nice hot spot. A very excellent $10 light. (This Rayovac is a very nice "cheap" light on its own.)
Now to my Fulton anglehead. I have been hesitant to mod this light in any way that it could not be easily returned to stock. The Lambda PR insert is excellent in this light. Looks to be about the same overall output as the Philips HPX22 Xenon I had installed. Of course color is much different. These SMJ PR2's are bright and bluish, but compared to the yellow of your stock incan 2D light they are a definite improvement.
Also, with 2D behind them these things should give very excellent runtime.
Mark