You say that your polks aren't loud enough. Replacing your speakers, even if you get ones that are a little bit more efficient, isn't going to make a very big difference in volume. I would suggest getting a more powerful amp.

You managed to resurrect a rather old thread :-)

Actually, my amp had plenty of power but my speakers couldn't handle it and would distort if I increased the gains on the amp. The polks where only rated to 35watts I believe and the kappas I ended up replacing them where rated for more like 85. Even though the MTX amp I am using is only rated at 25watts, the gains are still pretty low with the kappas and I don't get the distortion.

For some reason MTX amps seem to be underrated. The birth certificate for the one that drives my subs shows it putting out nearly twice the wattage ratted on the box.

-Mike