Thanks 2fasst, really appreciate the compliment.
I did the install when we had contacts at Fosgate so we went all out on the equipment
. Even Strike (Lightning Audio) is owned by Fosgate.
Yep, the 4 blocks you see are crossovers and I really didn't worry much about the distance to the speakers or tweets. I just made sure to use good speaker wire and paid attention to the connections so I wouldn't be faced with ripping anything apart afterwards. I am a solder freak so everything that needed it got a butt joint, solder and shrink.
For the harness, it would be vehicle specific and you are on the right track for getting the power to the head unit. Much easier to just use the adapter. Since you are using amps for the system just omit wiring the speakers connection from the head unit to the harness. Insulate the seperate leads with heat shrink and wire the speakers directly to your amps as needed. In theory you could tap in to the vehicle harness for your speaker connections from the amp but if you have tweets and crossovers it becomes a bit more complicated to pull that off and the tweets would likely need seperate wiring anyway. It also would depend on how the factory amp is phased in with the speakers. Safest bet is seperate wiring for the new speakers (just my opinion). For triggering power to the amps I just "t'd" off of the blue trigger wire to both amps and it worked fine.
Good luck and I hope some of the infomation will be useful. I took a lot of shots putting her system in and it took about 4 days since I pretty much gutted the interior while doing the install. So take your time and check connections and remember to test before finalizing the installation.
I just completed the install of my F150 and BT90 last week but no amps or subs (yet). I set up everything so I could easily add it later though 