It's designed to wire directly to speakers, factory or aftermarket.
Your plan is sound.
Go forth and purchase, young padawan!
Can this G4 connect through factory speakers? I'm planning to connect its through factory speakers and the subwoofers will go through alpine amp. I can connect it for it to work like that right?
Yeah you should be good Just as said b4 check to see if you have factory amp you may run into some headaches there ... otherwise straight forward install