Audio system HELP (OEM head unit)(3rd gen non-JBL)

Alright TW, need some help. Car audio is definitely not a subject I'm familiar with, and after a little bit of researching, I'm probably more confused. As the title implies, I'm hoping to build a system using the OEM Entune (w/ Nav) head unit (non JBL) in a (2016) 3rd gen. I'm really not aware of the different options out there that are "plug and play," but I'd prefer something I could do myself with no splicing into factory harnesses or too much custom work. From what I understand, I can use a $30ish LOC adapter harness/cable with the stock HU to run RCA and remote wire from the HU to the Amp (along with power from battery/ground to chassis) to utilize aftermarket subs, correct?

My next question is door speaker replacements; to actually get the performance out of aftermarket replacements, using the stock head unit, do I need an additional amp just to power the speakers? Depending on the sub amp, is it possible that the door speakers could be powered off of it as well?

 

$41 Add An Amp Amplifier Adapter Interface to Factory OEM Car Stereo Radio System for select Toyota Scion Subaru Vehicles- Add Subwoofer Bass Amp etc.- No Factory Premium Amp- Vehicles listed below

Amazon.com: Add An Amp Amplifier Adapter Interface to Factory OEM Car Stereo Radio System for Select Vehicles - Add Subwoofer Bass Amp etc.- No Factory Premium Amp- Compatible Vehicles listed below : Electronics

Something like this is what I've seen referenced to add an amp/sub using the OEM Entune unit.

 

@destin_meeks you seem to be incredibly helpful in other threads. Do you care to help me filter through my options for building a system? My current tentative plan would be add amp/subs and maybe subaru tweeters at this point, and aftermarket door speakers/amp (if needed?) down the road. Current amp/sub choice would be a pretty solid looking deal locally on some Rockford Fosgate P1's/RF Amp with Tacoma rear seat box. Any suggestions?

 

the first step is to figure out how much you really want to spend on it all.

the next step is to figure out what bothers you about the current setup.

 

total budget is unknown as of now. I'm fully aware that as with any type of mod, especially things that are subjective, like sound, people end up buying 2-3 times what they could've just started with from the beginning, and spent 1/2 the cost likely. As strange as it sounds, I think I'd honestly be happy just getting a sub with the stock setup. I'm not dissatisfied with the stock speakers, but I'd love more kick drum/bass guitar from the hardcore/metalcore type music I tend to listen to. Highs from the tweeters/door speakers can already be enough for my liking, but I'm lacking mids/lows. If I score big locally on amp/subs, I may be happy with just that, but also may have some budget leftover for some upgraded door speakers/tweeters. My big fear is that I add subs and then need to compensate elsewhere for the room (in the total spectrum of sound) that the subs now take up.

 

Well, if you insist on using the factory headunit, get an amp with a DSP. Something like the AudioControl D5.1300. You can send speaker-level signal to it, eliminating the Hi/Lo converter, and have a DSP to undo all the damage that the factory headunit does to the sound. Look up @dolbytone ‘s pics of the all-pass bands graphs Toyota did on the H/U.

 

I added a kicker 10” sealed enclosure 2ohm subwoofer with the kicker key 500.1 amp. it sounds great with the factory head unit speakers. It’s all plug and play with the factory harness and revoming the trims and installing the amplifier and wiring wasn’t too bad. I do have wires under the floor Mats, but it’s an access cab and I don’t care for passengers in the rear. Don’t even worry about switching out the rear speakers unless you plan on installing a subwoofer for the door speakers also.
Over all it sounds better than the JBL sound system I think. Minus having the extra treble of a Camry.