Chop one chipotle pepper. Mix all ingredients including chopped chipotle pepper in medium bowl. Place Top Sirloin Steaks in one gallon zip top bag and pour marinade over steaks. Seal well and place in refrigerator for 3 hours. Start grill and bring to medium heat. Remove steak from marinade, reserve marinade. Cook steak to medium, apporximately 6 minutes each side. While steak is cooking, bring marinade to boil in one quart pan, and continue to boil for 5 minutes, until it becomes a gently thickened sauce. Removes steak from grill to serving platter and let rest 5 minutes. Drizzle steaks with sauce and serve.