Does a drag race only car need exhaust boxes?

If your exhaust boxes are crappy and restrictive you could very well need a different tune up for when the exhaust is open. My car is fuel injected, with the cutouts open it uses 3% more fuel to hit the same AFR target, it is about .1 and 1mph faster with the cutouts open vs running through an exhaust system. This is a 3550lb A body Barracuda with a 418" small block that runs 10.40s.