When do I have to remove tokens?

Can I play spell in response as long as I have tokens on gathering the winds?

When do I have to sacrifice gathering the winds? Before or after the resolution of the spell i played?

Removing the tokens is a cost. Otherwise, see the lively discussion in this thread http://www.fantasyflightgames.com/edge_foros_discusion.asp?efid=140&efcid=4&efidt=669399 and wait for the upcoming FAQ entry on Gathering.

That's what i thought. Thank you for your response