EX-99.1 EXECUTION VERSION AMENDED AND RESTATED GUARANTY AGREEMENT THIS AMENDED AND RESTATED GUARANTY AGREEMENT (this "Guaranty") is made effective as of the 16th day of March, 2008, by JPMORGAN CHASE & CO. (the "Guarantor"), a Delaware corporation...Guaranty Agreement • March 31st, 2008 • Bear Stearns Asset Backed Securities I Trust 2007-Ac3 • Asset-backed securities • New York