I was kind of wary of attempting these at first due to the cost of the MPP turbo heads but the results made me glad I did.
MPP-1:
It's hard to improve on the LED/reflector combination in the MPP-1 so I left that alone and stuck to a simple 7135 driver swap for 3 brightness modes and full brightness from a single cell. To my eyes, output on high is slightly increased over the original driver with 2 cells and medium is roughly similar to the original driver on a single cell. The low is a "moonlight" mode perfect for when some extra light is needed without disrupting your night vision.
MPP-2:
The MPP-2 was a nice floody light perfect for a work light or lighting a large area while walking at night. I decided a LED swap and a driver swap was in order for this one. The MC-E was removed in favor of a T6 bin XM-L and a 3A 7135 driver installed in place of the original. The XM-L focused beautifully in the MC-E OP reflector producing a buttery smooth hot spot with no artifacts and an even, gradual fade into the corona with no evidence of the bright ring around the outside of the hot spot that my other XM-L lights exhibit. The spill has a slightly purple tint that seems typical with my other XM-L lights. Output seems to be very similar to the original configuration and the floody nature of the light has not changed.
The MPP-1 and -2 were gathering dust on a shelf because I would constantly reach for a smaller single cell light. Now that they are both capable of full output on a single cell, I'm hoping they will see more use and less shelf time.
Tony