Fast aircraft have to be a lot faster to make a real difference on a long trip. The main advantage with the gazelle would be fuel economy if that is something that concerns you. Fit your HKS turbo to the xair and there would not be much difference in speed, range between the them. I am minding a Skyranger with 100hp rotax in my shed atm, they are a great all-rounder if you can only have one aircraft.