Bit late on the reply but i got 2 rear door speakers you could of had.
is there actually a difference between the left and right speaker.

a bit off topic, but does anyone know which wire is the + and which is the negative.

my rear door has a splitter so there is 2 +'s and 2 -'s each with a big/small connection. I guess so they can be easily switch if you have the polarity wrong. However i've no idea which is which and as far as google goes it hasn't been very helpful.