Sauté shrimp heads and shells in 1 tbsp of oil for 2 minutes. Pour water and bring to simmer, Crush the shells with a ladle to extract more flavor. Simmer for 10 minutes. Strain and reserved stock.
Season shrimp and squid separately with 1 sachet each of MAGGI MAGIC SARAP®. Sauté with 1 tbsp of oil separately for 1 minute over high heat. Remove and set aside.
Sauté garlic and onion in the same pan with remaining 2 tbsp of oil. Pour shrimp stock and MAGGI Supreme Sarap. Bring to simmer.
Stir in noodles and cook for 5 minutes over high heat. Add carrot, cabbage, crab sticks, sautéed shrimp and squid. Cook for another 2 minutes.
Transfer immediately on a serving plate and serve with calamansi.