SlimSkinny9

I bought an 08 ES350 a month or two ago and have been struggling to find and figure out wtf i can put in this car. Initially beginning the search for wire harness kits to replace the deck in the car and it saying if i didnt have a certain system in it i wouldnt be able to install one due to potential safety concerns with wiring. I can barely find any info on the system or what i have and what my available options are.. so today i went and bought a RCA amplifier adapter because i was just going to wire them into the rear speakers, all while realizing in the rear center all it has is a tiny little subwoofer... so in short...lol am i now able to buy a specific wire harness kit attach for my old deck to attach to this car and be able to wire the subs and amp into like normally without any BS? ​​​​​​​