No surprise the option was exercised. From today's press release:
Southfield, MI, March 18, 2013 - Sun Communities, Inc. (NYSE: SUI) (the "Company") today announced that it has closed its previously announced underwritten registered public offering of 5,750,000 shares of common stock at a price of $45.25 per share, which includes 750,000 shares sold to the underwriters pursuant to the full exercise of their option to purchase additional shares. The Company estimates that the net proceeds from the offering will be approximately $249,530,000 after deducting the underwriting discounts and expenses related to the offering.
Net, net of 43.3965 was as I expected from the completed 424B5.