ya know srool, i'd love to do four lvl 4 12s over the three 12/15s truly. I have around $1200 or so i want to spend on the subs and heck i have a full sheet of MDF, plenty of screws and resin at home right now. But with four lvl 4m2s at 1400 rms each (5600rms for all four lvl 4m2s) and that means my 5k wouldn't really cut it, then again i'm running it at 15.3 with really no voltage drop now so i'll be pushing it trying to give each 1400rms and yeh i could just upgrade amps a lil later in which that DC7.5 is next ..... but then i face the issue of selling whatever i choose (three lvl 4 12/15s, or two 15xls) once i upgrade to the 7.5k.
So i'll think on it so the three or four lvl 4s will stay on the table or either the two 15xls. i've even thought about doing four lvl 3 12s although i'd be overpowering them a good bit (only by 350 rms......... also purchasing new coilovers/springs to lower my truck and a new set of 24s(not doing the 6s anymore) along with replacing the kinetik upfront for a xs power d6500 so yeh $$$ is the only thing that'll stop me from doing four lvl 4s.