I have an Alpine SWX-1043D Type X 4 ohm DVC 10" subwoofer and a Kenwood KAC-7205 2 channel amp. What is the best way to wire the sub to the amp and get the best sound. After reading on crutchfield, I'm thinking I should wire each voice coil to a separate channel on the sub to get 250W rms @ 2 ohms to each voice coil.

 

never wire VCs to seperate channels, you will cause damage to your speaker by any variance bewtween the channels.

DVC speakers are meant to have the VCs wired to themselves only, either in series or parallel.
If your amp is 2 ohm stable bridged youl be ok, something ma,kes me think it is not tho.. you simply have nto purchased gear that is proper for each other.
You need a 4 ohm sub.