One of the biggest bobos in sub history is the fact that the Seawolf is incapable of VLS launches, a massive oversight that led to this being corrected with the Virginia class. The 688I or Improved Los Angeles class is capable of VLS launches, as opposed to the original 688 which does not. The Tomahawks are fired through VLS tubes just behind the nose holding the sonar. Having the VLS tubes frees the torpedo tubes for real torpedoes which is an advantage if the sub has to suddenly face an opponent.
Going back to the Xia, at least we know in 2005 that the sub went into a refit based on the GE image in Qingdao. Its clear from the picture that a new propeller is fitted (shrouded), the power plant section is opened and so is the section at the torpedo room.