Melt margarine over low-medium heat and add olive oil, salt, pepper, hot sauce, lemon juice, and bacon. Simmer for 2 minutes. Allow to cool.
Place the cleaned crabs on plate. Liberally coat the crabs with the sauce, making sure to lift the sides of the shell to coat the meat inside. Save remaining sauce for basting. Cover the crabs and allow to marinate in the refrigerator for at least 2 hours.
Heat grill to medium-low.
Place crabs on grill topside down. Baste with remaining sauce while they cook. Cook crabs about 3 to 4 minutes on each side. The crab will crisp on the outside and the meat inside will turn white.
Remove from grill and serve topped with Grilled Vidalia Onions.