The Supernova Crossing . . . over

What's the best Crossover brand name unit (qualitywise) on the market to connect a pre BAT-30SE (no sub-out like the Receivers) to an active subwoofer (Earthquake Supernova MKV-12)? Or would there be a way to connect the Sub without a Crossover and still get the same quality? ... and what would be the suitable cable/interconnec to use?
Besides the above 2 units, my system includes a Classe CA400 amp driving a B&W 802's.
Any input is greatly appreciated.

From the desk of a newbie audiophile fan.
Just connect a good pair of subwoofer RCA interconnects from your Bat preamp output connection to the sub, your Bat should have at least 2 pre outs. That's the way my supernova MKV-12 is connected and it rocks.