Quote Originally Posted by MLA View Post
Kicker KXMA800.8 or Wet Sounds HTX-6 would be go-to's.

A couple of basic line level control knobs would give you tower and in-boats volume. The WS-420 SQ or BT would give you 3 zone level control, so you are setup for adding a woofer later.
I agree with MLA on the recommendation of the KXMA8008. you can use AMP1 and AMP2 to run the 4 in-boat speakers. Then you can use AMP3 and AMP 4 in bridge mode to drive the two tower speakers. This setup will deliver basically perfect RMS power to all speakers. Then to add to the recommendation, you can use the FRONT fader output of your head unit to control level of the in-boat speakers and REAR fader output to drive the tower speakers. This way you can control the two areas independently without the need and added cost of an outboard volume control.

Phil
Kicker