amp to use high input from back speakers, where is the wire?

Hey all,

After alot of reading I bit the bullet and bought a small powered amp for under the seat of my 2004 prius, the question is this:
I want to splice into the back speakers into the high level input on the amp, but I cannot find where a good place to get to those wires would be, I do no have jbl or nav. I really dont want to take the door appart or the dash, as I always break clips. Most all threads I have read have been specific to jbl installs. Am I better to use the high lvl input on the Amp or use a speaker to rca conversation?

Thoughts and help much appreciated.

 

Found this, does anyone know the paths these take to get to the rear speakers? That would be most helpful.

Thx

2004 Toyota Prius Stereo Wiring InformationRadio Battery Constant 12v+ Wire: Blue/YellowRadio Accessory Switched 12v+ Wire: GrayRadio Ground Wire: BrownRadio Illumination Wire: GreenLeft Front Speaker Positive Wire (+): PinkLeft Front Speaker Negative Wire (-): VioletRight Front Speaker Positive Wire (+): Light Green/WhiteRight Front Speaker Negative Wire (-): BlueLeft Rear Speaker Positive Wire (+): BlackLeft Rear Speaker Negative Wire (-): YellowRight Rear Speaker Positive Wire (+): RedRight Rear Speaker Negative Wire (-): White