Does kicker count as part of the spell's mana cost for effects that care about how much mana was spent?

A spell's mana cost is the cost printed in the upper-right corner of the card. Kicker is an additional cost you may pay when casting a spell (CR 702.33a), and paying it does not change the spell's mana cost or its converted mana cost/mana value (CR 202.3).

Effects that care about the spell's mana cost or mana value — such as cost-reduction effects or abilities that check whether a spell's mana value is above a threshold — look only at that printed cost, not at any additional costs paid, including kicker (CR 601.2f, 202.3).

However, some effects are specifically worded to care about total mana spent or total cost paid to cast a spell. In those cases, kicker payments would be counted because the question being asked is broader than just the mana cost (CR 601.2h).

Example: You cast Burst Lightning kicked (paying {R} + {4} kicker). If an effect asks 'did you spend 5 or more mana on its mana cost?' the answer is No — the mana cost is just {R} (mana value 1). But if the effect asks 'was 5 or more mana spent to cast it?' the answer is Yes, since total mana paid was 5.

So the distinction hinges entirely on whether the effect references the mana cost/mana value specifically or the total amount of mana spent casting the spell.