if you run at 4 ohms, then you will have to get an amp thats rated way higher then you need since the 4 ohm load will kill the output. most amps are rated at 1 or 2 ohms so at 4 you will only see about half or 1/4th that rating.
cant make them 2ohms, either 1 or 4 ohm, run a 2 channel bridged like around 500-600watts. if it is a prefab jl box, that is how they come wired with 2 subs.