question about paying kicker cost and counterspell in mtg

[Soddda]

When I play a spell that has a kicker cost like Benalish Lancer

Do I get to decide whether to pay the kicker only after other player decides whether to counterspell it or not? (obviously I wont pay the kicker if he is going to counter the spell)

[Arix]

No. You pay the whole cost - including kicker - all at once, before any player gets the chance to respond.

[Chodie]

It is an additional cost to play the spell, so yes it is all together.

[Tad]

since a kicker is part of the mana cost of the spell does it add to the spell's color for example is a Cetavolver considered blue, red and green?

[Arix]

No. A card's colour is determined by one of three things:
1. The mana symbols in its cost (in Cetavolver's case, it's just blue, regardless of whether or not the kickers were paid).
2. Text that gives it a colour (like with Wheel of Fate).
3. An outside ability giving it a different colour (Tidal Visionary).