Mix together 1/2 c olive oil and 1/4 c balsamic vinegar in a small bowl. Arrange 4 fillets salmon in a shallow baking dish. Rub 4 cloves pressed garlic onto the fillets, then pour the vinegar and oil over them, turning once to coat. Season with 1 tbsp fresh cilantro, 1 tbsp fresh basil, and 1 ½ tsp garlic salt. Set aside to marinate for 10 minutes. Preheat your oven's broiler. Place the salmon about 6 inches from the heat source, and broil for 15 minutes, turning once, or until browned on both sides and easily flaked with a fork. Brush occasionally with the sauce from the pan.