I feel like this is one of the most well-realized precon decks ever out of the box, so you dont necessarily need to change 30% of the cards straight away even if I told you to jam a few games, talk with your group about the power level you want, and then decide where you want to land on the scale between AFR Set Constructed Venture Tribal and Legacy Reanimator Combo
The rate of this pair has led to the deck playing progressively more copies of Arena of Glory over time, which then makes it harder to include more cards of colors that aren't red
What I love about this sideboard is that the deck remains focused on its game plan even after the sideboard cards come in
Uncapping the mana available to players at the start of the game makes it more reasonable to allow potent attacks on mana, like Wasteland, Daze and Armageddon, adding a whole new strategic element to the game
Spells cast from zones other than your hand and spells that were countered or otherwise failed to resolve are still counted by the coststorm ability
1 Non-foil Booster Fun rare or mythic rare