Just A Simple ?
 

i was wondering is it capable for us to keep the stock hu in our cars while putting a sub and amp in i kno u can do it but i dont want to like ( I DONT KNO THE WORD)but im gonna say bridge one of my speaker in the back but can u "bridge" the factory sub in the back and just take that sub out and use that wire instead of bridging a "sound speaker" thanks for helping.

So you want to take the signal wire off of the stock sub and drive it with your own amp?
Or bridge another sub on the stock amp?

hey
 

i want to bridge it with a amp so i dont lose any of my sound (vocal speakers) is it possible?

get an output converter

Buy a good amp, almost all of them come with a high level input with a low pass filter built in.