I'm starting an audio system install because I'm tired of the blown speakers I've already changed my rear door speakers to JBL six by nines. But I don't think they sound nearly as good as they should. I would also like to add some speakers in the dash. And some midbass drivers in the front doors. Future plans call for a sub in the rear. What I would like to know is if the amplifier wiring Is present on a non Bose model? I have a 04. Trailblazer LS four-wheel drive i6 non Bose audio Thanks in advance for any help.