So I had two 2005 Caddy Devilles. My first had radio install, plug and play with aftermarket speakers in doors with amp to run to all four 5.25 door speakers. That car is gone now I have the same radio from the last caddy and would like to know if I can just put the old aftermarket radio in and that already has the kit and wire harness. Plus can this work if i change all the speakers (2-ohm) and use an aftermarket radio. i really want to do everthing myself but caddys are tricky. any help is great. thanks. looking to buy new door speakers 2-ohm.