Using large knife, cut corn kernels from cob. Heat 2 tablespoons oil in heavy large skillet over medium-high heat. Add garlic; sauté 1 minute. Add corn; sauté until just cooked through, about 5 minutes. Remove from heat. Add half of basil.
Transfer corn mixture to large bowl. Cool slightly, stirring occasionally. Stir in tomatoes, vinegar, 3 tablespoons oil and remaining basil. Season with salt and pepper. Cover; chill 3 hours or up to 8 hours.