The mini will be unable to drive the speakers at anything like acceptable audio levels. You will definitely need an amp. I've never seen a screen with an integrated amp, and it's unlikely that the heat from an amp would be good for an LCD screen, but perhaps others have seen something I have not. If you're happy with the relatively low power level of the stock head unit, you should be able to get a pretty economical 4-channel amp. Your options will also depend on if you have the 4 or 6 speaker system or the Rockford Fosgate subwoofer. I recommend you do some research on a site like DIYmobileaudio.com or a similar forum as well.