The increase Lumen output of the 9V SureFires compared to the 6V SureFires means that the beam is larger - more light - not more intensity. This is the case for example the P60 and the P90.
That said, the larger diameter reflector of the M3 means the beam is more intense and has better throw. The M3 has the ability to overwhelm a target more easily then the 6P. The increased Lumen output allows you to see more, more quickly. The increased Lumen output gives the beam more impact when directed into the eyes of a target.
I can easily tell the difference between the E2e and the M3 beams.
not only is the beam from my M3 on its lola brighter than the P60 in my C2, its also larger. i can literally light up my whole house with the backsplash of light from shining the M3 on the ceiling /ubbthreads/images/graemlins/smile.gif
I go dog walking with my GF in a dark greenbelt area, she with her E2e that I gave her for Christmas, I with my M3 running the MN11. Mine seems about twice as bright, and lights up about twice the area, so my answer is YES, huge difference!!