:bs: I will have to raise the flag on this post...
3-10" subs WILL NOT BREAK A WINDSHIELD! It is impossible!
Speakers are basically air pumps. The produce sound by moving a volume of air. To break a windshield you must be able to pressurize the inside of the cabin, producing failure of the window. Could you have cracked windshield from another source, that is made worse by 3-10's... yes.
I have been in the "Linear power" van that had over 4000 watts of power, running 12-12's (this was true watts, not Pyramid wattage claims). They did not beak a stock windshield. When the volume is turned up it is almost impossible to breath!