What does a resonator do?

Well,I mean besides the obvious answer--restricting exhaust flow and pulling down HP and TQ numbers. Can I just ditch it when I put in a decent exhaust or is it best to keep the set-up the way it is. This is a 91 5.0 BTW.....
thanks

ditch it. A good unit (not stock) shouldn't resist flow very much. Mufflers on the other hand will be a little more restrictive.

Get some kind of high-flow resonator... you don't want to go without if you are using your bird as a daily driver, the drone is awful.