A. I'm not going to give you an answer, because if you ask 100 different Virago Tech users, you'll get 100 more different answers. The best I can do is link you to a site called "Gasoline FAQ", a four part series that will give you all the facts and help you choose the best gas yourself.
Comments: Personally, I use a very simple rule for choosing the right gas: I start with whatever grade has the least amount of Octane, and if the engine develops a "ping", I move up one grade. If it still pings, I move up another, until I run out of higher grades. (Octane is merely a chemical additive that does nothing but cause gasoline to burn slower in an engine, so that it doesn't pre-detonate, the condition that causes the "ping" noise when it's running.) If you use a grade that has too much octane content, the unburned residue can build up and possibly cause damage to the valves and pistons.

Additional Information. Yamaha recommends "Regular". That's 87 RON (Research Octane Rating).