You really need to forget the amp altogether.
Your kenwood head unit probably puts out 45-55 watts per channel, which is already ideal. No need to pipe the signal through an amp.
Bypass the stock amp and you will be happy, I promise
If you'll take a picture of your stock amp and a closeup of the wiring at the amp, I can verify your setup and tell you what wires to cut and splice to bypass.
You should be able to do it all in the frunk. No need to pull the stereo or get into the dash.