How to setup my new subs.
 

I already have a 12" kicker l5 in my trunk and am looking at adding two 8" subs in my backseat in a custum consul. The 12" will handle the low bass while the 8" handle the midbass. Should I hook up the two 8" mono and have them face up or should I hook them up stereo and have one each facing out each side? I'm also looking at adding 4 tweeters so ill have 11 speakers total. Any tips are appreciated.

If that is where the midbass are going, it makes little difference if they are mono or stereo.