I like the dark ambience although it honestly strikes me more as mood music for gameplay as opposed to a race theme. The first thing I pictured while listening was some tense gameplay scenario like navigating through a dark and dangerous environment while something scary is watching/stalking you.
Don't mean to sound critical but the melody is very atonal because the key signature seems way off, or the timbre has been altered with some kind of filter. Don't know if it's intentional but I think it would sound great with the correct pitch/notation left intact.
I took a very different approach with my Mycon concept theme, but I really want to try doing an homage or remaster of the original eventually. One of these days I'll stop making excuses and just do it ...