bad to fire subs in opposite direction?

I couldn't find this anywhere specifically, but will I lose bass by firing 2 10" subs in opposite directions?  I will be building a center console in a minivan to conserve useful space but want to get the most out of it.  I already have the subs but if using one would give better results, then I'd rather do that.  I may be able to fire them downwards - just don't know if that would be a good idea?  Any tips would be appreciated!

Thanks!

I think he is placing both woofers in a console of a minivan.  They will possibly be firing one to the left side of the vehicle, and the other firing to the right side of the vehicle.  Wiring the woofers out of phase would definitely result in much less bass. 

Hey guys,  thanks for the tips.  I'm new to forums but I have to say, this is a great site.  I'm a fairly inexperienced shadetree (or actually "driveway in the middle of the night") type of installer.  I've done a few, but it's been a few years since and I have a lot to learn.  That being said, I did this a few years ago in a former Toyota Sienna: I built the box between the two front seats as to not take up any family/storage room elsewhere.  The subs were in their own seperate chambers, one firing forward and the other firing into the rear (with cupholders on top - hence a center console ; )  I've wondered ever since if I should have done it differently because I've heard over the years about bass waves cancelling each other out sometimes.

My wife and I miss our sound, and I was wondering if I could get more out of it this time by changing the direction of firing.  Are there any drawbacks to downfiring?  What is the minimum amount of space I need between the subs and the floor?  If it matters, the subs are some old Crossfire 10s.

Thanx!

btw - anyone else out there with a minivan doing a stealth install to save the vehicle for it's intended use (hauling the family and stuff)?  Or am I just the oddball?  : )