Just a higher octane fuel mix, impractical unless you are doing a short run.
There is a thread here LINKY with a link to a French firm that sell a kit of carb bits and a different sprocket. I would not recommend drilling jets BTW. Since you have a custom set of pipes on it, it does seem practical to look at a re-jet. Never owned a Virago but changing the gearing and re-jetting could be a cheaper, effective, option.