Consider separating find friends vs invite friends
While it may functionally be the same re: importing address book, one of the predominant fear for those of us when joining any network with social features is that the system would self promote and send emails to people not already int he network, generating a highly undesirable spam effect.
You want your users to trust your system. Adding wording of guaranteeing that you would not do this self promotion is key before I am got to enter my gmail info and let you survey my 5000+ contacts, many of whom I do not have daily contact with and will treat any such potential email blast hostile.
you can remove permissions here, https://security.google.com/settings/security/permissions