Well, kickers are designed to get loud, but they sound like absolute garbage as far as sound quality. Sealed boxes are for SQ not straight loudness. Id put them in a ported box, around 16cf net, probably tuned @ 32 or 34 hz. Youll need around 20ft of external gross space to work with if you wanna do those 4 15s ported. If you cant put them in the right box, youre wasting your time. I dont think youll have any more than 10cf net back there to work with though. Might be able to do 3 15s" but 2 18"s have slightly more cone area and would be louder.
I can take my 2 15s ported on 2kw and blow 4 sealed out of the water, hell mine was way louder than a guy with 6 12s running more power than mine. Its all in the enclosure though.
But to run just the sub stage for 4 L7s youll atleast need an HO alt, 4 runs of 1/0 to the back, and probably a battery bank of atleast 4 100ah batteries. A good rule of thumb is 100ah of reserve capacity per 1kw of power. Id run probably 1500w to each one, and get the dual 2 ohm models for better wiring options. Look into audiopipe AP1500 mono amps on ebay, solid amps for a good price and do rated power.
You need to drop your budget on engine mods, its not a racecar, its a nissan SUV. If youre serious about the sound then youll need to budget yourself atleast 2000 more to finish the entire thing, this is given you do all the work yourself, and already have the L7s. If you have to buy the L7s, budget another 1200. IIRC theyre about 300 a piece on ebay. Audiopipe makes really good stuff for the money, look into it on ebay.
