The Amp I Have Will Run The L7 At About 750w Rms, I Talked To The Guy At Kicker And He Recomended The L7 Over The X Due To The Amount Of Power, He Also Recomemded A Box At 1.94 Cubic Feet With A 4 Inch Port 6 Inches Long
I'd go L5's before going L7's unless you plan to put over 800 RMS watts to each L7... Takes a lot of power to make them come alive...
I have L5's in my boat, and a few of my friends have L7's.. Unless your pushing mega power to them the L5's seem to work better.
RD