Still shopping

just bought my 2008 LS 460 with 6.99% on 706 fico scores Interest rates are great at 4.9 and under... Got 3.9% from LFS last month; This is my third transaction with the company in the past 10 years. So does lexus offer special financing rates certain times of the year? My wife and I are shopping for rx 350 '09, just not sure whether we should wait for "deals" or not