Boil macaroni according to package instructions. When done, drain pasta and transfer to a large mixing bowl.
Pour vinegar over the hot macaroni along with chopped peppers, onions, celery and pickle. Toss to combine and then allow pasta to cool completely.
While the pasta is cooling, in a small bowl mix mayonnaise, mustard, sugar, salt, pepper, paprika, milk and garlic powder.
When the pasta is completely cooled pour dressing over and mix to fully combine. Cover pasta salad and place in the fridge for at least an hour before serving.