2 inch exhaust??

If you're looking for improvement and keeping the cost down, try going 2½ to the muffler and leave the rest at 2". This is similar to what Mopar did with the single exhaust Commando/Charger 273s.

I'm told that dropping the interior pipe diameter at the tail pipe helps maintain exhaust velocity and improves the scavenging effect of headers. Never tried it personally.

FWIW: The Dart has a 2¼" system front to rear with a turbo muffler. The Demon has 2¼" tail pipes. Depending on what I can do with the exhaust manifolds, I'm thinking about doing a 2½" exhaust pipe and muffler. If that won't work out, I plan on 2¼" all the way.