Amp configuration

He is a list of my equipment that I plan to install in my boat.  The 6.5's are going into cans, two per, on the wakeboard tower.

Alpine CDA-7845 HU (19 rms x 4) Coustic XM-3 crossover Pioneer Gm-X252 2 channel amp (40@4, 50@2) Sony XM-3040F 4 channel amp (30@4, 40@2) Pioneer 4" KFC-1077 - 18 rms - Under rear bench Alpine 6.5" SPS-170A (2) 40 rms - Tower Alpine 6.5" SPA-174A (2) 40 rms - Tower (components, but not separate) JBL GT650T 6.5" Ported Sub (20-80 rms) JL Audio 10W3 D4 Dual Voice Coil Sub - Sealed (75-500 rms)

I plan to run the 4" Pioneer's off the HU. Each speaker can is set-up for two speakers. One decision is on how to configure the 170 and 174 (together or mixed).

My other debate is on whether to run the JL or the JBL sub, as each one present different possible configurations. If I use the JL, I lean toward bridging the Sony and hitting the JL with the 160 rms (40@2 x 2) since the sub is in a sealed enclosure, that would leave me to run the four tower speakers at 2 ohms on the Pioneer which would give each 25 rms. If I use the JBL I can power it with the Pioneer bridged at 100 rms, which is slightly over what it is rated but no much. I could then either bridge the Sony and run the towers in series, or just have a dedicated channel for each speaker. I would lean toward bridging just because of running half the number of wires up the tower. I am thinking I may just settle for the JBL, I know that it will not sound as good, but it will allow me to run the tower at 4 ohms, and not worry about pushing the Sony, as it is old.  It (jbl) is also much smaller and easier to place inside the boat. Plus the majority of what I listen too doesn't have a heavy base component-heavy base seemed to miss the Bluegrass movement, but Steve Earle does have a thump from time to time. Yes I am a redneck, but a highly educated one, more like a YURNie (young urban redneck), than YUPie.

What do you think? Should I consider running the JL with just the 80 rms the Pioneer can give and still run the tower off the Sony? Does it matter where I place the sub inside the boat? Concerning the tower speakers, should I mix and match the 170 & 174's. The 174's are component with an external crossover (will put inside the can). I have read some about acoustic coupling and did know if there would an advantage to pairing the 170 & 174 in the same can. Since the crossover (xm-3) has three outputs I had considered passing the 170's at a higher frequency than the 174's (i.e. 170 @ 300, 174's at 100), but didn't know if the difference would be minimal, plus it is more of a hassle if I mix the speakers within the can. Sorry so long, but this forum seems to contain some audiophiles that could actually help me.

I probably should have broken it down a little more, but have a tendiacy to provide too much background.

I think I am going to just use the JBL sub, it will meet my needs and be easier for me to install on all fronts.

My biggest question now, is whether to run a separate channel for the four speakers on tower or bridge the amp and run the speakers at 8 ohms.  Will this actually provide that much less power to the speakers? 

I have read that you can change the ohm load by using a crossover.  The theory is that by eliminating certain freq depending on the speaker (i.e. 150 on a co-ax) that less power is consumed and the load can be changed.  I was curious if I ran the speakers parallel (2 ohm per can), and crossed them over at 150, if I could move the draw closer to a 4 ohm load that the amp could handle bridged.