I have done more or less the exact same modification as described by netprince.
LED: XM-L T6 3C tint from cnqualitygoods
Driver: 1.4A driver from shiningbeam
Reflector: LEDiL Boom-W
Here are comparison shots. The unmodified lamp is a Varta and not Rayovac, but they're exactly the same thing other than one being grey and the other being green. The camera had the same settings, especially aperture and white balance so you can see the difference. They are using the same set of batteries - 6x fully charged GP Recyko AA cells in 2xAA to D-cell adapters