I have added one 10 inch sub with a 2ohm mono amp. I want to upgrade the 6X9 to a full range speaker. I know the signal to the stock 6X9 is low. Is there a way to wire in a full range speaker without adding another amp for the aftermarket 6X9's?

 

Tap the rear signal into the rear door speakers for a semi-full range signal. The rear door speakers have a bass roll off but at what Hz I don't know.