So I created a mod on Nexus, my first actually, that replaces Data Xigbar's music with Kenny's theme from Attack on Titan, since they're both the same archetype and are both quite cool. It's slightly more complicated than a typical track replacement, because Xigbar's reaction command requires specific loop points to be made. This ended up making it even better, as the showdown is a lowkey, almost tense couple of measures of music, and the post-showdown music takes you straight to the crescendo.
I think it's worth a try even if you're not an Attack on Titan fan.