2016 Entune JBL w nav - adding amps & subs

I thought the 2016 Entune JBL w nav sound quality would make me happy but it does not so I want to add 4 Polk speakers, 2 polk amplifiers along with a polk sub - and keep the head unit.

Besides giving tacotune $350 or paying a stereo tech for 8 hours of bypassing the stock amp, is there another way?

If this is covered elsewhere, please advise. Searches and other threads seemed to go nowhere near answering this.

2016 TRD offroad longbed

Thanks for your help!

 

A nice start would be if someone has the wiring schematics for the single, access, and double cab models that should include the Entune system they would be willing to share? I know nice wish! I just like to improve my system and to start with it would be helpful to know which wire goes to what and where?