In a M*glite, the Xenon Star bulbs in my opinion will give an almost lazer 'spot'. But will STILL not open up to a flood for crap.
I have used Xenon Star bulbs in some other lights (I have NEVER overdriven one though) and in some lights, TEC 40 for one, I find them a HUGE improvement over other bulbs.
Driving a 2 cell Krypton bulb with three cells is not very good for bulb life. Driving a 3 with 4 is good stuff! And the ratio gets better as we go higher!
I have a 3D with 4C in it, and it is a wonderful light.
And don't forget to order some Acrylite lenses!!! They can make the most AWFUL M*g beam a thing of beauty!