No Export for You - Quite a few of their videos WEREN'T available in Germany. Fortunately, they're all available now on the official channel.
The Other Darrin - Played with: in "Maximum Protein Experience", Muscles Glasses is replaced with someone having a similar body build and trademark sunglasses. When Epic Mook notices Muscles Glasses working out at the gym where they're filming at, Harley tells the extra they don't need him anymore.
Played with again in "Epic Stockyard Burger": Harley's absent to do the video intro, so Tyler fills in for him...until Harley walks out from the store and tells Tyler to go out, buy lunch and do his proper job.
In "Meat Mummy", Muscles Glasses wears a costume that turns him into... a random black guy. The rest of the guys (sans Harvey/"Beard Lightyear" and Cousin Dave as "Tony Hawk") wind up dressing up as Muscles Glasses.