Kub3, image shack delete images after a while so we can' see my old pics. Despite its thickness, the cone is VERY light and it doesn't move that far to get down to 30Hz, much due to the use of a transmission line which provides near ideal acoustic impedance loading of the driver.

Talking of light weight cones… I don't think light is the ultimate goal for bass. You need it ridged as well. The cone in my Eminence 12" drivers is very stiff and probably quite heavy (mms 75.3g) but the absolutely huge magnet still gives it a lot of control with a fast rise time. The cones damping is also important to the decay rate. In other words you need to strike a compromise!

Shin, for a driver with a near perfect impulse / step response look at the Manger  Indeed, it is VERY dynamic.

Nick, I'm sorry to say you system will not likely achieve that level of SPL. You need to take in to account the cones maximum excursion and thermal power limit not just its sensitivity and power available. The midrange will probably be the weak link for SPL at the lower range of its ability. Probably more like 110dB SPL.