To run both speakers right you are going to need 1200 watts rms. Although a good brand amp (or two) with less wattage will probably be more than loud enough for you. I have one 12" L5 in a Kicker box, and started using a Rockford Fosgate punch 200 amp, and it was unbelievably loud (ran that setup for 4 years). When I got a new car about a year ago I picked up a sony 1200 watt amp and honestly it isn't much louder, so the brand makes a huge difference (you just have to pay a whole lot more for them). They say underpowering a speaker is worse for it than putting the correct wattage to it, but those Kicker solobarics are monsters, and as long as you don't overpower it you should be fine. Honestly though, two L5 12"s getting 600 rms a piece is going to be overkill, I couldn't imagine my system being any louder with just the one!! I can literally shake things off the shelves in my house if I crank it up in my driveway.