For the "I want it now" folks... I propose this: Build your quad 660, so that you will have your laser now. Every paycheck or 2, replace one of your 660s with a 640 (provided you are using broadband optics). That way, you still get your laser right now, and as you progress, so does the apparent brightness. This will make it so that you don't drop a ton of money at once, or you won't have to save up for months to get the laser that looks great. Aftyer a few months, viola, there is your quad 640 and you will have 4 660s for spares or another build. Just sayin....