change sub in GM bose system

i have a truck with the bose system can i just change the stock sub to a different one or what is involved?

We changed out the factory sub in an Escalade once with a JL 6w0. The customer INSISTED. Had to reinforce the crappy Bose plastic enclosure, had to bypass the crappy Bose amp and wire in an aftermarket one. After several hours and $400 in product and labor it sounded almost just like the factory sub....maybe worse. My opinion: you're spinning your wheels here. If you want more bass but want to keep a stock look, JL makes a great center console Stealth Box you might want to look in to. If you can stand to stash a sub somewhere else, please do.