I just traded my 2 15" mtx 9500's for 2 18" Fi BTL's fully loaded. I have a dodge magnum so I think i'll only be able to get 1 sub in the back cuz i refuse to build a wall in my car. Unless I could get 1 sub to fire down into the spare tire sport and have the other face the hatch. I could lie and tell people it's just one sub the only amp i have right now is my mtx te4001d. i'm pretty sure that won't satisfy both subs even though it's over 3750 rms @ 1 ohm. Thinkin about goin with sundown amps. i've heard nothin but good about those amps.