Stop in for a cup of coffee

Afternoon all! Question regarding exhaust. My car came with TTI headers, and Im not sure of the exhaust system. However out of the headers it necks down from 3" to 2.5", through some Dynomax Turbo Mufflers which reduces again to 2" at the outlet of the muffler, then out the back of the car.

So for those of you that know exhaust, would I get any benefits out of changing the mufflers and tail pipes to 2.5" to keep it consistent straight through?