I completed my L3 cert in November 2008. And while M motors are really cool, I won't be flying many of them due to cost. But, I like the option that I can if I want to and friends of mine make motors.
But, I have to agree with the majority here and ask the question WHY do you want to do your L3? Do you even know the fun L1 and, especially L2 motors are? In the right rocket, J motors can be fantastic and IMO a K motor is really where the action is. Those only require a L2 and, as others stated, the L2 grants you the other privileges like RSO and participation in research launches. The only additional benefit an L3 grants you is larger motors in bigger rockets at higher cost.
The point is to enjoy the ride to whichever cert level you decide. I did my L2 certification within about 3 or 4 months of my L1. But, I waited 3 1/2 years between my L2 cert and my L3 and had tons of fun in that time. Even with the L3 cert, most of my flying will be in the I,J and K range with the infrequent M flight.
There have been plenty of fliers who got into the hobby, got obsessed with obtaining their L3 as quickly as possible, and once they achieved that they felt there was nothing left for them to accomplish so dropped out of the hobby just as quickly. Gain experience, try new things...there's plenty one can do at the lower power band to make things enjoyable, exciting, and adventuresome without the need for the L3. I'm not discouraging you from an L3, only questioning why so quickly and what will you get from it once there. If you want the L3, approach it methodically and have fun on the ride to it, but don't be one of those who finds rocketry after L3 as uninspiring and drop out before you really started having fun.
