[theminiv]

No no no, i hope i got this right,

Never put a live speaker signal in the inputs of an amp, unless it states that it has a compressor inbuilt for fluctuating audio signals.
An amps input is as important as the output, you can blow both. so dont, the inputs can only take 4v inputs, and can speakers are banging out 10 V, so at high volumes you could blow the input sector.

you must take a line out of your head unit. But if you have the stock unit you will have to have the plug to adapt it, V Expensive.

Be careful!!!!!