To prepare sauce, heat oil in a medium saucepan over medium-high heat. Add onion and garlic; saute 5 minutes or until tender. Add nectar, 3 tablespoons sugar, and vinegar. Bring to a boil; cook until reduced to 1 cup (about 15 minutes). Add bourbon, ketchup, Worcestershire, and red pepper; cook over medium heat 2 minutes, stirring occasionally. Remove from heat, and stir in the lime juice. Cool slightly. Pour the sauce into a blender, and process until smooth.
To prepare steak, combine 1 tablespoon sugar and next 7 ingredients (1 tablespoon sugar through black pepper); rub over both sides of steak. Place steak on grill rack coated with cooking spray; grill 7 minutes on each side or until desired degree of doneness. Cut steak diagonally across grain into thin slices. Serve with sauce.