Radio question

[gsy4771]

I have been researching this site and a few others with regards to replacing the radio in my 04 base. I'll admit I am confused. It has a factory amp in the front which I think will give me the most issues. I have been reading that 03/04 cars have the MOST bus which sounds proprietary. I cannot figure out if all 03/04 cars with amps have the MOST bus. I was really hoping just to install double din unit and use the existing amp and speakers, really only installing so I can get Apple Play.

1. Is this s simple adapter from Crutchfield?
2. If I were to replace the amp also, can I use the existing speakers?
2a. I know the door speakers are subs so I'm guess they would need replaced.


I'm trying to avoid gutting everything and pulling new wires, more of a project than I wanted.

I would love some advice on #1 and #2 from above and if I'm on the right track.

I was hoping to be in the $600 budget, dual din and amp.