Wireless or wired?

Also a cable run would be in the neighborhood of 40 feet for each sub. 

Subs work fine with ordinary hookup wire. Subs aren't super responsive to wire quality the way full range speakers are.  So I would think they would work fine with wireless. For sure the benefit of adding those subs is greater than the difference in how they are connected. If that's what's holding you up relax, and go for it.

@millercarbon. Thanks for your input. With subs being Omni directional will placement still be important ?