I really do love what you've done here, its definitely a nice take on the themes used. I think the clipping is just the bass drum being too loud, if you turned that down a little and just maybe messed with the EQ slightly (so you don't lose the power) would sound awesome.
As for the transition to the underground theme, maybe a quick pause then the sound effect of going down the pipe might make the transition a little more fluid. The bass isn't too shabby, maybe with the bass drum lowered in volume you wouldn't get that slightly static/clipping sound.
Overall though, i think maybe the instruments are still too loud. Are you running a compressor on the track? If not, try using one on the whole track and using an EQ on the whole track to really bring out the highs and lows better.
All in all, i like the overall tone of this. Especially the underground theme, the big band sound really come out in this. Keep up the good work, its well on its way.