You know what you should do...
Instead of spending all your money on good speakers for the front (where it counts the most), you should pay someone to run wires to the back so you can install the shitty factory speakers back there this way you can have matching shitty fronts and backs and destroy the sound stage while your at it.
-maybe that will get a response.

 

Running the wire for the rear speaker is just time consuming.
Get some decent wire, maybe even some HD speaker wire if you plan on upgrading the speakers later on.

Take off the door steps and the side panel inthe front and the rear.
Feed the wire from the radio area out each side to the door under the step and on to the back.
An alternate would be to run the wire up the middle, under the floor covering, snake the wire to the back.

A couple of things to keep in mind:
Keep the wire connection the same, from "+" to "+" and "-" to "-".
Keep all of the speaker wires the same length; on some lower powered systems this may not make a difference but it doesn't hurt, this applies to the fronts too, all four the same length.
Use a good grade wire, better than good if you plan a speaker upgrade. No sense in running wire twice.

Sorry if this a dup on any comments made but I would do it this way AND if thinking future upgrade spend as much as I can on the speaker wire.

One more thing... Rear speakers can sound good, you don't always need a sub and amp, although an amp on the four speakers is a good idea.

Good luck with the system...