I think I will be shooting you a pm I am having trouble thinking of the best way to do this. My problem is if I sum them together I will have to cross the signal over again. I prefer to not use the crossover on the amp. I know some of the audio control units are alot better then the crossover units built into the amp. The other issue I was thinking about the less the signal has to pass through the better.
As far as tapping the wires I was thinking about just grabbing the signal where it meets the speakers. And running the signal from there to the processor. That way I don't have to tap into any speakers so for some reason if I have to return to stock it won't be a problem.
I am very familiar with car audio but this mustang there are so many ways to achieve the same or near the same results. It's driving me crazy. Lol.
This is not true. What you will do is use the front channel RCA outputs from the LCQi to the Channel 1/2 channel input on your amp, and use the bass RCA outputs from the LCQi to the 3/4 channel inputs on your amp. All of the signal cross over and tuning will come from the LCQi. That's what all those adjustments are for on the top of the unit.
What sub / subs do you plan to use and what impedence are they? This will make a difference as to how you bridge channels 3 and 4. The 8w7 is 3 ohms, so if you plan to bridge this across channels 3 and 4, you need to make sure the amp is stable to 1.5 ohms. My preference is to keep subwoofer impedence at 2-3 ohms. If you used two 8w7's wired in series and then bridged at the amp, that would be a net 3 ohm impedence. Although i am not sure your amp is large enough to power 1 sub let alone 2.
2012 GT CS Ingot Silver Vert, Edelbrock E-force supercharger with CAI and 3.5 Pulley, Tremec T-56 Mag, Accufab 84.5, Centerforce DF, Billet Yoke aluminum driveshaft, FRPP 3.73 Rear, MRT Performance H-pipe, Bassani axle backs, JL Audio sound, Edelbrock strut tower brace, JPC adjustable UCA, UMI adjustable panhard bar, KW V3 coilovers, Steeda heavy duty front mounts, Steeda rear LCA's, 20" Steeda Spyders with Michelin Pilot Super Sports, Steeda Big Brake Kit ....... it just keeps going.