Cook the elbow macaroni according to package instructions. Drain and rinse under cold water to cool.
In a large bowl, combine the cooked macaroni, corn, cherry tomatoes, red onion, feta cheese, and cilantro.
In a separate small bowl, whisk together the mayonnaise, sour cream, lime juice, chili powder, salt, and pepper.
Pour the dressing over the pasta mixture and toss until everything is well coated.
Cover and refrigerate for at least 30 minutes to allow the flavors to meld.
Serve chilled, garnished with additional cilantro if desired.