Boil the pasta in a large pot of salted water until al dente, about 8-10 minutes. Drain and rinse under cold water.

Prepare the shrimp by boiling until pink and opaque for 2-3 minutes, then cool and chop into bite-sized pieces.

Chop the celery, red bell pepper, and red onion into small pieces.

Whisk together the mayonnaise, sour cream, Dijon mustard, lemon juice, Old Bay seasoning, salt, and pepper in a small bowl.

Combine the cooled pasta, shrimp, imitation crab, vegetables, and dressing in a large bowl, tossing gently.

Refrigerate the salad for at least one hour to meld flavors.

Garnish with parsley and paprika before serving.