L7's are good speakers, i have 4 of them and 1 solo-x and they slam, but like stated in earlier post, sq is not nearly as good a a w7 would be, solo's put out a RAW thump, i personally would go with the w7 if you have the money and you don't need a $1000 amp to push it, you can find QUALITY amps that push out the power necessary to power your subs

and you don't need to get a more powerfull alt. i've had 2 solo 12's and 1 solo-x in my civic with just a second battery and my lights don't even dim. if you have the money tho, and want the xtra power, i would definatly buy one.