Understanding that TECHNICALLY you should use oil in keeping with owner's manual guidance, of the two oils you are contemplating, I would go with 10W30. Given your climate, the type engine and the performance characteristics of the oils, the 10W30, I think, is better for your application. It is more shear stable and has a more consistent UOA track record (as I recall) than the 5W30. If we had more data, and it were easier to find, I'd really like to recommend German Castrol 0W30 BUT at this point I could only advise you based on personal bias/expectation rather than demonstrated performance. As you watch the UOAs become more frequent for that oil, you might want to keep the idea in your hip pocket. Remember, if it proves shear/grade stable, the 0W should not be a concern even in Florida heat, because it is the 30 weight portion of the rating (and the performance of the oil at that end of the temperature spectrum) that will determine the thickness and strength of the oil layer protecting your engine during most of the time it is operating.
[ August 10, 2003, 02:25 PM: Message edited by: pscholte ]