If you've got a Dual 4 Ohm sub then your options for wiring it to that amp are pretty limited.
That amp is stable @ 4 Ohms or 2 Ohms per channel in stereo and 4 Ohm only when in bridged mono mode.
Meaning with that amp and that sub you're going to want to drive one voice coil per amp channel and you'll need to use a DMM to match the two channels' outputs pretty precisely.
If you don't then the voice coils will not move in unison as they should and that can lead to premature driver failure...and nobody likes that. //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif