alot of times resonator deals with more than noise, it sets a speed bump for the catatlyst. It is even a set distance from the cat by good engineers. it is often a chamber to allow a quick burp, then slow...to make the cat REALLY function. Every off throttle, and on throttle.
on injecteds with air bypass, the exhaust is not bothered much, with or without,hence the resonator hack on modern turbo cars..it is screaming through the pipes anyway at all times there. For n/a cars, it needs math.
I went into quite an experiment deciphering exhaust for a low pressure carbed car...the highest mpg on planet earth - (for you metrompg)
it still needed a resonator, but nearly hollow, to mimick what fat injected intakes do for the catalyst. The echo could take a more open baffled one and possibly increase mileage, but unlikely. Exhaust
Too hot is a good sign to mess with resonator.