Is there some threshold for FICA calculations?

Is there some threshold for FICA calculations?Joe is president and 75 percent owner of JS Corporation. He takes a salary of $825,000 this year. Presidents of comparable companies are generally paid no more than $500,000. What are the income and FICA tax consequences if $325,000 is determined to be excessive wages by the IRS? Assume Joe is in the 35 percent marginal tax bracket and JS Corporation is in the 34 percent marginal tax bracket.