crossfires are a good bet, those atomics are nice too
the mojo 4kw's CAN do it but not only do you need a beasty *** electrical, itll probly still run warmer than it needs to. I personally wouldnt run the mojo daily at .5ohm (.35ohm DCR) unless you can run at a MINIMUM 14v full tilt. I've heard that if you go under 1ohm you'll want do be doing 16v, under 14v they freak out if you're under rated imp.
this is coming from the guy i bought my 4kw off of who was running 8 or 10 of these iirc.