full audio set up questions

[nat3d]

ok right now im running a single 12" type r off a m500 mono alpine amp and a line output converter. im loking to finish my system with loosing the line out converter getting a new head unit replacing and amping my speakers. first off am i going to have to go up to higher gauge wire from my battery and alt if i amp my speakers? second how much am i going to loose (functionality wise) when i replace my head unit? and anything i should know about picking a head unit?

 

[bobshur]

4 gauge will be ok.

 

[bobshur]

You will lose imid audio screen, steering wheel Bluetooth phone controls , you can keep sw controls fir head unit but get axxes, it works best.

 

[bobshur]

By the most you can afford, the nice and expensive ones offer everything, I went with the alpine ine-920 s love it!