To TS, I think I can share some experience.

Not driving a FLX but Preve.
Not happy with stock speakers, went for a combination of 2ways component speakers + amp.
Crossover din install though as recommended by the installer where my amp is good enough to handle all the 4 channels. Rear speaker? Disconnect the wire.

So far, I'm pretty satisfied with it. The sound not really till dashboard yet but not far from it. At least not on the floor anymore.

If u into music listening, dun use the FM modulator.....

Happy hunting.

a player with USB input, is much better than using FM modulator.
Even if it just 320kbps MP3.
I would say change HU first.

This post has been edited by allenultra: Oct 19 2012, 07:46 AM