Thanks guys! I've never installed a tri-mode amplifier. I think I'm starting to understand the concept a little more after some research and some reading. You guys have definitely pointed me in the right direction and I think I'm going to give this a shot. I'm a little discouraged by some of the response I've had (including fellow installers that I work with.

), but not enough to stop me from going on with it.
I still have a few questions being as I have wired bridged amps and stereo amps but never a tri-mode, bridged/stereo, at the same time and am a little curious as to what my ohm load should look like for the "mono/bridged" output on the amp and if that effects the stereo ohm load at all. In the diagram provided for example, without the sub wiring connected, the ohm load would be normal stereo output at a certain ohms with the crossovers installed. But, after adding the subs onto the outside channels, will it effect the stereo channels in a way that I would need to check the ohm load in a certain way or does the amplifier see it as three separate outputs (if you look at it as stereo (2) and mono (1))? I am trying to look more into understanding how the amp identifies the different outputs and how it distinguishes between them and whether it "combines" the ohm loads when the sub is added into the equation. If anyone can give me some insight into that, it would help alot.
I do need help with the crossovers that I will be using as Phoenix Gold is recommending that I use 12db slope crossover on every speaker. I know that the component set that I am purchasing is coming with an 18db slope crossover "box". Should I just wire in my own "new" crossovers at 12db slope for the right frequency? That's what I'm considering after reading the owner's manual where it states, (from the link in one of my posts on the first page) "...6db and 18db per octave crossover slopes don't short because they are 'in phase.' However, 6db slopes don't filter the frequencies outside the passed band effectively, and 18db slopes can be cumbersome if not ineffective because the slope varies according to the speaker's impedance. No speakers impedence is a flat 4(ohm) across its frequency range, which means your crossover will not have the slope you expect it to have at a given frequency. In real-world terms that means you have no way of predicting what your crossover slopes will actually look like."
All of that to explain why not to use 6 or 18db crossovers which makes me want to use 12db crossovers.
And, about the 12db slope crossover, "...A 12db per octave crossover (an inductor and capacitor for each speaker) forms a series resonant circuit to ground whose impedance at a particular resonance frequency is determined by the speaker's dynamic impedance at that frequency. If the speaker circuit, for whatever reason, becomes "open" or disconnected, the crossover impedance is theoretically zero (0)--a direct short. Most amplifiers do not like to see this condition, but Phoenix Gold amplifiers are designed to withstand this type of treatment and allow you to use an easy-to-control 12db slope."
So after all of that being said, does a 12db 100Hz low-pass filter have an ohm load of 4 already or does the amp see the ohm load from the actual speaker, or is it all combined making 2 ohms? This is what I really need to figure out before buying my speakers and, yes, after reading all of that I couldn't find the answer!! LOL!!
Installer for life.