The best combo would be dual 6ohms. You could wire it to 4ohm mono or 1ohm mono. Wether you go 4 or 8 though, depends a lot on the amp. 8 ohm will give you a 2.6ohm load, 4ohm will give you 1.3. You'll need a monoblock amp stable that low. If it's 2ohm mono stable, get the 8ohm, if it's 1ohm mono stable, get the 4 ohm.