Heat the olive oil in a 16-inch fry or braising pan with high sides (3 inches) over medium heat. Saute garlic and shallots until opaque, 2 to 3 minutes.
Add crabs in the shell and cook, stirring occasionally, until juices leak into pan and crabs are turning red, 5 to 7 minutes.
Add the wine.
Bring to a boil and cook for 2 more minutes, or until the wine has cooked off and juices have thickened.
With tongs, transfer crab pieces to a large ovenproof serving bowl; cover and keep warm in a 200-degree oven.
Add tomatoes (including juice) to pan.
With a wooden spoon, scrape any crab bits from the bottom of the pan.
Cover and bring to a boil over high heat, stirring occasionally.
Add half of the cooked crabs, fresh herbs, red pepper flakes and salt and boil gently, uncovered, stirring occasionally and crushing tomatoes with a potato masher or spoon. Reduce heat as sauce thickens, until sauce is reduced to about 4 ½ cups, about 30 minutes. About 15 minutes before sauce is done, in a 6- to 8-quart pan over high heat, bring 3 to 4 quarts water to a boil.
Add pasta, stir to separate, and cook just until barely tender to the bite, about 6 minutes.
Add cooked pasta to the crab/tomato sauce pan and stir well.
Add the fresh crabmeat (if using) and stir gently but thoroughly.
Bring to a simmer over medium heat for about 2 to 3 minutes.
Mound pasta in a wide, shallow serving bowl. Remove the remaining cooked crabs from the oven and arrange on top of the pasta.
Sprinkle both crabs and pasta with parsley and serve.