I drive a 4 door grand am, planning to cut a 15" sub into the back
seat, build my box accordingly.
I've seen mixed opinions about speaker location and such, but I plan
to build at least one set of pods on my doors, should I put a second
set of components in, say the back? or another location? I figure if
they're in back I won't really be able to hear them, but it is nice to
have that extra sound.
Any advice on this would be helpful

this is the speakers I plan to use, just need to know how many sets to
get (the sub is a 1999 hcca 15d, so I'm sure especially where I'm
putting it, it will be hella loud)