Sneak and Show wants to cheat Griselbrand, Emrakul, the Aeons Torn, or Atraxa into play via Sneak Attack or Show and Tell, so Disruptor Flute naming Sneak Attack taxes it by {3} and is a cheap, flash-speed hedge against their namesake enchantment. The extra Mystic Forge adds redundancy to our own combo plan so we can race them to a lethal turn before they assemble their payoff, since this matchup is fundamentally a speed race with little real interaction on our side. Mishra's Research Desk and the singleton Mox Opal are lower-impact and fine to trim for a touch more resilience. We keep Karn, the Great Creator in since it shuts off activated abilities of artifacts they control, such as their Lotus Petals, and it still fetches our key artifacts from outside the game. It does not affect Sneak Attack, which is an enchantment.