sub or amp

Hey guys, I own a Genesis gv70 2.5T select with the base 9 speaker system. I don't know much about audio systems, but I know enough that the base speakers on the GV70 are pretty lacking. They don't feel like they have enough depth, and listening in low volumes doesnt create the best experience...

Has anyone tried taking out the factory Sub and putting in an aftermarket Sub in the same location? What are the deminsions of the factory Sub including depth?

Very easy to do with a little electrical and audio knowledge. 10" alpine type-r 2omh dvc jl audio xd600/1 pac 50a loc 8 gauge wiring kit Wasnt looking for over the top booming bass but rather something to compliment the stock system without going overboard. I think I accomplished my goal but...

Does the stock nav unit have a preout for a subwoofer RCA? Id love to keep it, and utilize my amplifier/subwoofers I already own. I dont own a Genesis but Im looking at the Coupe, most likely the 3.8 GT or Track model Thanks guys