mid-song tempo transition is fine, but I really think you gotta give it some more time. More specifically, letting that crash ring out and giving your audience a chance to 'reset'. Always try to think about it from the standpoint of someone who's never heard it before. Try making it feel like the ending and the beginning of a new movement. The pause could be a cool spot to drop a vocal acapella part that crashes into the up-tempo version of the song.

Mix improvements are a given, but tighten up that arrangement first! Nice work overall.

Yeah I totally understand. Actually having some vocals spoken and its more of a placeholder right now.