How fast is fast? If you have the G51 then something fast then perhaps the Shrike or Diamond Dust. I think the G51 would be great as it can turn perhaps a 10x8 comfortably. The Shrike on a TT46 will go about 90 mph and climb so well. That's a good choice if you have a grass field.

The F20 from Sportman Aviation is a nice plane, flies fast enough but not terribly. My favourite 'fast' sport plane is the WM SS40 with my Rossi 45 turning a 10x6 at 15,000 RPM, everyone hates that engine, its just so loud.