Seems like the best oil to use is as hard to identify as the best gasoline to use. In the end, I think it's all up to the individual to decide. I use Royal Purple 10W40 Synthetic automotive oil and change it, with the filter, every 5,000 miles. Why 5,000 miles, it's easier to notice on the odometer. I used the same oil in our old 2008 SE5 for 40,000 miles with no issues. The valves were never adjusted and didn't need adjusting when the tech checked them before reselling the Spyder.
When it comes to warranty, the only thing oil will affect for warranty is the engine. How many riders have had engine related problems due to oil?
On our 7.5 week, almost 14,000 mile trip in 2009 on our SE5, I made the whole trip without changing the oil. Just added oil when needed...2 quarts total. So, I am sold on Royal Purple, as I am on Chevron gasoline to keep the plugs clean, etc. Changed the original plugs on the SE5 at 28,000 miles. Could have probably gone another 20,000 miles.