In a large saucepan, heat 2 tablespoons of the olive oil with the garlic over medium heat. When the garlic starts to sizzle, pour in the tomatoes. Season with salt and red pepper. Bring to a boil. Lower the heat, and simmer for 30 minutes, stirring occasionally.
In a large skillet, heat the remaining 2 tablespoons of olive oil over high heat. Add the shrimp. Cook until the shrimp turn pink,do not drain. Add shrimp to the tomato mixture, and stir in the parsley.
Make a cornstarch slurry, set aside.
Cook sauce until it just begins to bubble. Add slurry, mixing well.
Then bring a large pot of lightly salted water to a boil. Cook pasta for 8 to 10 minutes, or until al dente; drain.