Izzet Affinity's only real artifact targets in the main deck are Giant's Boulder (their mana rock and late-game removal), so Ingot Chewer's ETB destroy-target-artifact ability is a modest answer to those. It can't kill The One Ring, which is indestructible, so don't count on it to deal with that card. The extra Trumpeting Carnosaur copies give us more discover-5 card advantage to grind through their countermagic-heavy shell (Force of Will, Force of Negation). We trim Tibalt's Trickery since countering into a random cascade-style spell is unpredictable against a deck full of expensive spells that could get cast for free off the top, and we cut two Violent Outburst since its cascade hit rate is lower value than the extra bodies and card advantage here. Watch for effects like Kozilek's Command exiling cards from our graveyard, and prioritize Boseiju, Who Endures to blow up Urza's Tower-cycle lands if needed.