Managed to get things working

Now looking for a recommendation on which amplifier to use. Any idea.

I’m looking at Alfa Romeo GT 3.2V6 with a Bose stereo. I assuming I need to change out the base amp.

Looking good! I am guessing the current amp has no aux input? I use to have an alfa GT myself, and I can’t quite remember the audio set up from it, I think I even have the old Bose amp kicking around. But an aftermarket amp should do the trick if it supports aux input, or you may need to get a HAT that can do RCA output.