What year? King or Crew cab?

My answer will be as if you have a '12 crew (that's what I have) yours may vary slightly (i dunno that the kings have a separate rear door tweeter)

You will be OK with the rear doors...the two drivers are close enough together to just run a short wire from the x-over to the new tweets. (or cut the factory wire and put it in there...but then you got another plug to mess with)

The dash tweeter/front door speaker is where you will need to think a little...

If you must will use the crossover that came with the speaker set, and are planning on putting the tweeters in the dash, I think it would be easiest to fish a wire down from dash tweeter to door, or vice versa depending on where you want your crossover to live.

If you don't want to do that, and feel adventurous, you'd have to find where the wires to the door and the wires to the dash are connected together, and drop the crossover in there.(they split somewhere between the head unit connector M168 and the M8 and M75 connector in the kick panels...maybe someone else knows...id bet either end.. not in the middle).

I don't like altering factory harnesses,(to the point where I cut the OEM speaker connectors off the OE speakers so as not to disturb the oe harnesses) and tend to add wires for alterations like this so it can be undone simply.

In my case, as I had purchased separate tweeters with their own high pass filter, I left the harness alone (dash and door are parallel), and just installed the HP filter in the wire at the tweeter, and dropped my door speaker tweeter level by 3db.
(I do plan to Bi-amp my front end as soon as I find an incredible deal on an amp... and will then need to run wires down from the dash tweeters to that amp.)

EDIT:
I also used a plug adapter set for the factory speaker and power connector at the HU .. so I have RCA cables from the HU to under the seats(amps there), and speaker wires from the amps back up to the speaker plug adapter.
Now that I type this.. it does sound kind of lazy... but it worked great for me.

 

It's a 2012, CC, SV, and I'll be running new speaker wires. I went with a Pioneer HU, Infinity component speakers and Rockford Fosgate Prime amp.

 

Best bet is to just pull new wires through. It's really not that much of pain. Plus then you won't have the headache of integrating factory and aftermarket wiring.
I have a whole custom system, JL audio components with their crossovers. I mounted the amp on the passenger side rear and ran the wires up to the crossovers underneath the passenger front seat, then to the doors from there. It was a solid two day and once case (of beer) project. Totally worth it and next time I will be dynamating everything.

 

Best bet is to just pull new wires through. It's really not that much of pain. Plus then you won't have the headache of integrating factory and aftermarket wiring.

^^ He's right... ^^

(I'm just lazy and hate pulling wires through the pillars and door booties, then tying em up neat so they don't hang up on the window when it comes down and all that...I guess after pullin' the rest of the wires I did to get the amps and sub in... 6 more woulda been ok...)

 

Got everything I need I think, I was reading somewhere that I may have to use adapter plates to move the speakers away from the window in it's down position. I'm going to be using FAST rings. Does anyone know anything about adding adapters and/ or using FAST rings. 6x9's in front, and 6 1/2's in rear.

 

Got everything I need I think, I was reading somewhere that I may have to use adapter plates to move the speakers away from the window in it's down position. I'm going to be using FAST rings. Does anyone know anything about adding adapters and/ or using FAST rings. 6x9's in front, and 6 1/2's in rear. 6x9's have a depth of 3 1/8", 6 1/2's have a depth of 2 1/16"

 

I own a 2012 King Cab SV that I replaced the head unit with a Pioneer AVH4100NEX with HD audio. All I can say is wow what a difference. The bolts that held my head unit in were metric. So I replaced them with studs. This makes taking the unit in and out a snap.

So next, I replaced all 4 door speakers with Alpine 2 way coax units. The oem speakers weren't that bad, but the Alpines were a definite improvement.

If I had to recommend you do one thing. I would say to put some sound deadening material in the doors. I did all 4 incrementally.
Titans have large spaces in the doors that turn them into huge tin drums. Most of the road noise was entering through the rear doors.

 

1quiktitan -

Did you ever complete your install? Got any install pictures to share? My wire crimper is on the way so I'm running out of excuses not to do my upgrade... I also bought the fast rings on the recommendation of a friend so was wondering how you set everything up...

Thanks