Stereo or mono on 2 channel amp

Could be a big difference, one that will send your amp into sudden death.  Or could be no difference at all in power output.  Depends on the ohm resistance of each woofer.  If they are 2 ohms each, you could give them each a channel...but paralleling them and bridging to the amp will let the smoke out.  If they are 4 ohms each, they can each get a channel...but paralleling them and bridging to the amp will let the smoke out.  But in both these cases the woofers could be linked in series and bridged to the amp........

As in most cases, give the specs of the equipment you're asking about (or post a link), for useful advice. 

Are you talking about the 4 ohm DVC's, subject of your previous thread?  If so, bridge like this

The amp will power the subs with the same power output as it would if you connected each sub to separate channels....but with the voice coils wired differently, like this

I would normally choose to use the bridged method:  Same mono input to each sub, possibly more forceful impact to the bass response, and less wiring to the speakers.  Two subs normally share the same enclosure, so wiring them to each other is preferred over wiring each one out to the amp individually.

the speakers are hooked up like this

+ ____________ -

+ ___           ____ -  

         l           l

are u saying that if i hook it up like the second diagram that i can get a combined 2 ohm load? that would be great