If you want rear facing subs, the best way do it is to have a forward facing port, and wire the subs to fire backwards. Not as accurate as forward facing, but a good trade off between punch and boom.

 

2nd the fact that they need to be facing forward. some will say the sound will resinate off the trunk, but that is poppycock. not trying to brag but i have had more than enough sub/amp combinations in my day and have found that forward firing subs are best. not only if you want them loud, but for a more accurate reproduction of the sound. however, i will stand by my previous statement that no matter what you decide, dynomat your trunk first. you cant go wrong

 

The bass is WAY louder and sounds 100x better in the cabin of the car with a direct fire sub...

 

Computer issues..

 

i got 1 cheap mtx 10 and its plenty man. youll appreciate 1 sub (whatever size) and having more trunk room in the long run