A search will come up with a ‘how to install a Kenwood’ it has all the adapters listed, but you should do the pizzaguy suggestion and get full control of the radio as best you can with the OEM amp.
I found out that my rears worked just fine, it felt like a kick in the kidneys if you wanted.
The Kenwood install question was asked in the last week as well.
Kenwood Install (click)