In a saucepan add a touch of olive oil, plum tomatoes, 3 shallots and 4 cloves of garlic and cook until shallots are translucent. Add white wine and juice of 2 lemons. Bring to boil, reduce heat, let cook three minutes. Remove from heat and add all ingredients to blender and puree. This process may require being done in steps so that blender does not overflow. Strain pureed ingredients through chinoise, throw out pulp, reserve broth. Bring broth back up to at least 110 degrees. Place in a clean blender, add cubed butter with blender on high to emulsify, thicken sauce, season to taste.
In a large pot bring to boil salted water and then cook pasta to al dente, refresh in ice bath and set aside. Toss in 1 tablespoon olive oil until ready to serve.
In a blender, add 2 cloves of garlic, 1 shallot, basil, parsley and watercress, juice of the 1 remaining lemon, cover blender, turn on high. Slowly add 1 cup olive oil until emulsified. Season with salt -- add fresh cracked black pepper (a lot), briefly turn blender on. Transfer contents into a squirt bottle and refrigerate until ready to serve.
Place 1 saute pan over high heat until it smokes.
In another saute pan place 1 teaspoon of olive oil, add 3 ounces of pasta, then 4 ounces of tomato sauce, check for seasoning of salt and pepper to taste.
In smoking pan, heat 1 tablespoon of olive oil. Season scallops with kosher salt and freshly cracked black pepper, then add to hot oil. Sear deeply until warm brown color turn each scallop over and finish in a 375 degree oven (for 3 minutes). In desired plate or bowl place pasta with sauce, when scallops are done arrange them on top of pasta. Liberally swizzle pesto over plate and garnish with purple basil sprig.