Tip: When determining a time limit, remember that players won't be as familiar with the level as you are. If you normally complete the level with the timer around 100, others might run out of time on their first try.
Here's another one of many obscure SNES ports that people make all the time in this site which most people barely even give a fuck when it comes to the game and even the soundtrack itself outside of the fact this one port "sounds cool"...
Alright, alright, I'm just joking around, but here's a port/arrangement/remaster? of the Chapter 4 theme from Syvalion for the SNES, also known as Battle ~ Descending to Heaven according to the official OST release. It's a very intense song with a bit of odd time sprinkled into it, but also has tons of prog and funk throughout. Definitely could fit something like a final castle or anything else that matches it's feel.
NOTE: If you want to insert this, use the optimized version. I've still added the original version of the port here tho if you can use that somehow.