[Vivtek]

my mashup suffers from this in a few places

No. Not to this unexposed ear. I detest bad mashups, but if there are audio flaws in this one, you've concealed them very well indeed. I'm floored.

This makes me want to get on with my own back-burner electronic music notions.

[sharkbot]

Agreed. The end of the Bloodhound Gang section is slightly discordant, but I felt that it had an interesting sound and lead well into the final section. Great work.

[ehsanu1]

The Bloodhound Gang's chorus is probably the worst part of it, and is probably primarily what the OP was referring to, though the rapping verses work reasonably well. That said, it was still great overall.