Place rice noodles in a bowl and cover with room-temperature water for 1 hour. Strain off the water, then pour hot water over noodles for a few minutes until pliable but firm. Strain well and set aside.
In a small saucepan, combine palm sugar, water, Thai tamarind paste, fish sauce, and MSG. Heat over medium-low heat for 3-4 minutes until sugar melts completely. Remove from heat.
Heat 2 tbsp oil in a large wok over medium-high heat. Cook shrimp for 1-2 minutes per side until pink and cooked through. Remove and set aside.
Add remaining oil to the wok. Sauté chopped shallot, garlic, and cubed pressed tofu for 2-3 minutes until golden and fragrant.
Add the strained rice noodles, and pour over the Pad Thai sauce. Stir-fry for 2-3 minutes until noodles absorb the sauce.
Push noodles to one side, crack the 2 eggs into the empty side, and scramble gently until soft curds form, then fold into the noodles.
Return cooked shrimp to the wok, add 2-3 cups bean sprouts and garlic chives, and toss for 30-60 seconds over high heat until slightly wilted. Turn off heat.
Serve hot with chopped toasted peanuts, fresh lime wedges, extra bean sprouts, garlic chives, and chilli flakes.