Sub replacement

Hey. I just bought a 2015 GX w/Mark Levinson. Everything about the levinson system is first rate except the subwoofer which is weak. Anyone here know of a drop in replacement driver? I was thinking about the JL Audio 6W3v3-4 but I can't seem to find any consensus on whether it will fit without modification and if it'll work okay with the stock amp. Thanks in advance for any help...