Upgrade head unit

[shade]

I already have sirius with the RB4 unit but if I upgrade to another head unit will I need to buy another tuner?
What about the factory amp will that work? Crutchfield says I am SOL on that.

 

[Venom Power]

Dude I would just yank out the whole OEM system and start with an aftermarket set up.. You can even retain your steering wheel controls with an aftermarket head unit if that is an issue. I did with my ALPINE/NAV/DVD/iPod/XBOX set up.