01 Acura Bose sub stock

Ok so i have a 2001 Acura TL and the speakers are crap, it came with a Stock bose sub in back that i think is blow. The speaker is a weird size i wanna upgrade to a better one like JL audio or pioneer But i dont know what size will fit or if i need to make ask 5 star audiio to make the hole bigger in some way....Can some one tell me the size of the stock sub in the back seat and what they did to replace it....???????